Redmine

I've just set up a fresh install of:

OS: Ubuntu 14.04 LTS
HTTP Server: Apache/Passenger (Apache - 2.4.7)
Ruby version: ruby 2.0.0p481 (2014-05-08 revision 45883) [x86_64-linux]
Rails version: Rails 3.2.19
mysql  Ver 14.14 Distrib 5.5.38, for debian-linux-gnu (x86_64) using readline 6.3
redmine db encoding: utf8

Server locale:
> username@hostname~$ locale
> LANG=en_US.UTF-8
> LANGUAGE=en_US:en
> LC_CTYPE="en_US.UTF-8" 
> LC_NUMERIC="en_US.UTF-8" 
> LC_TIME="en_US.UTF-8" 
> LC_COLLATE="en_US.UTF-8" 
> LC_MONETARY="en_US.UTF-8" 
> LC_MESSAGES="en_US.UTF-8" 
> LC_PAPER="en_US.UTF-8" 
> LC_NAME="en_US.UTF-8" 
> LC_ADDRESS="en_US.UTF-8" 
> LC_TELEPHONE="en_US.UTF-8" 
> LC_MEASUREMENT="en_US.UTF-8" 
> LC_IDENTIFICATION="en_US.UTF-8" 
> LC_ALL=

The DB is migrated from an earlier 2.4.2 install.

I've noticed some of my user's are getting intermittent 500 errors when logging in (or if they're logged in through cookie, when trying to browse certain pages), in the morning or when the server's been idle for a while.
I've noticed the production.log also spitting out the wrong timezone in one case from the same browser (checked that user's timezone, if that helps)?
We're in the /Europe/Stockholm timezone, second 500-error in the log below says Dublin?

Checking my production.log it tells me this:

Started GET "/users/36" for [MASKED IP] at 2014-08-19 08:10:51 +0200
Processing by UsersController#show as HTML
  Parameters: {"id"=>"36"}
  Current user: [MASKED LDAP USERNAME] (id=36)
  Rendered users/show.html.erb within layouts/base (22.1ms)
Completed 500 Internal Server Error in 114.7ms

ActionView::Template::Error (cannot load such file -- tzinfo/definitions/Europe/Stockholm):
    45:
    46: <div id="activity">
    47: <% @events_by_day.keys.sort.reverse.each do |day| %>
    48: <h4><%= format_activity_day(day) %></h4>
    49: <dl>
    50: <% @events_by_day[day].sort {|x,y| y.event_datetime <=> x.event_datetime }.each do |e| -%>
    51:   <dt class="<%= e.event_type %>">
  app/models/user.rb:437:in `today'
  app/helpers/application_helper.rb:231:in `format_activity_day'
  app/views/users/show.html.erb:48:in `block in _app_views_users_show_html_erb__531584968933002312_63249760'
  app/views/users/show.html.erb:47:in `each'
  app/views/users/show.html.erb:47:in `_app_views_users_show_html_erb__531584968933002312_63249760'
  app/controllers/users_controller.rb:76:in `block (2 levels) in show'
  app/controllers/users_controller.rb:75:in `show'

[...omitted log output...]

Started GET "/my/account" for [MASKED IP, the same as above] at 2014-08-19 08:10:58 +0200
Processing by MyController#account as HTML
  Current user: [MASKED LDAP USERNAME, same as above] (id=36)
  Rendered users/_mail_notifications.html.erb (17.9ms)
  Rendered users/_preferences.html.erb (5.2ms)
  Rendered my/account.html.erb within layouts/base (33.5ms)
Completed 500 Internal Server Error in 43.2ms

ActionView::Template::Error (cannot load such file -- tzinfo/definitions/Europe/Dublin):
    1: <%= labelled_fields_for :pref, @user.pref do |pref_fields| %>
    2: <p><%= pref_fields.check_box :hide_mail %></p>
    3: <p><%= pref_fields.time_zone_select :time_zone, nil, :include_blank => true %></p>
    4: <p><%= pref_fields.select :comments_sorting, [[l(:label_chronological_order), 'asc'], [l(:label_reverse_chronological_order), 'desc']] %></p>
    5: <p><%= pref_fields.check_box :warn_on_leaving_unsaved %></p>
    6: <% end %>
  lib/redmine/views/labelled_form_builder.rb:42:in `time_zone_select'
  app/views/users/_preferences.html.erb:3:in `block in _app_views_users__preferences_html_erb__4280354043280162759_69854225159020'
  app/helpers/application_helper.rb:1050:in `labelled_fields_for'
  app/views/users/_preferences.html.erb:1:in `_app_views_users__preferences_html_erb__4280354043280162759_69854225159020'
  app/views/my/account.html.erb:43:in `block in _app_views_my_account_html_erb___4541838569531402333_63105120'
  app/helpers/application_helper.rb:1043:in `labelled_form_for'
  app/views/my/account.html.erb:9:in `_app_views_my_account_html_erb___4541838569531402333_63105120'

I saw an earlier topic having almost the same problem, but he considered it solved after reviewing his filepermissions.
About that time i got log output as described in the field below this paragraph.
I've reviewed the filepermissions/ownership (www-data:www-data, 775) on the server, and it looks like it's fixed the problem below.

Link to previous topic: http://www.redmine.org/boards/2/topics/43627

Started GET "/my/page" for [MASKED IP, the same as above] at 2014-08-18 12:58:05 +0200
Processing by MyController#page as HTML
  Current user: [MASKED LDAP USERNAME] (id=3)
  Rendered news/_news.html.erb (0.0ms)
  Rendered my/blocks/_news.html.erb (10.4ms)
  Rendered my/blocks/_timelog.html.erb (5.5ms)
  Rendered issues/_list_simple.html.erb (19.0ms)
  Rendered my/blocks/_issuesassignedtome.html.erb (44.5ms)
  Rendered issues/_list_simple.html.erb (14.7ms)
  Rendered my/blocks/_issueswatched.html.erb (27.8ms)
  Rendered my/page.html.erb within layouts/base (90.3ms)
Completed 500 Internal Server Error in 97.4ms

ActionView::Template::Error (cannot load such file -- active_support/multibyte/unicode):
    17:       <td class="project"><%= link_to_project(issue.project) %></td>
    18:       <td class="tracker"><%= issue.tracker %></td>
    19:       <td class="subject">
    20:         <%= link_to(issue.subject.truncate(60), issue_path(issue)) %> (<%= issue.status %>)
    21:       </td>
    22:     </tr>
    23:     <% end %>
  app/views/issues/_list_simple.html.erb:20:in `block (2 levels) in _app_views_issues__list_simple_html_erb__1225784539915115850_55538840'
  app/views/issues/_list_simple.html.erb:11:in `each'
  app/views/issues/_list_simple.html.erb:11:in `block in _app_views_issues__list_simple_html_erb__1225784539915115850_55538840'
  app/views/issues/_list_simple.html.erb:2:in `_app_views_issues__list_simple_html_erb__1225784539915115850_55538840'
  app/views/my/blocks/_issueswatched.html.erb:8:in `_app_views_my_blocks__issueswatched_html_erb___4220156679842397938_70106790870080'
  app/views/my/page.html.erb:20:in `block in _app_views_my_page_html_erb___3817531552599329398_56507780'
  app/views/my/page.html.erb:17:in `each'
  app/views/my/page.html.erb:17:in `_app_views_my_page_html_erb___3817531552599329398_56507780'

I just barely have time to login to the server to review the production.log, before they're reporting that it's working again.
I first thought it was a cookie/cache thing on the client side, since sometimes changing their browser is working. But that could perhaps be because of the time delay of when their next request are going out to the server?