Redmine

I put a request on users.xml.

User that logged in for the last time on redmine 2.1 get a xml-well-formated last_log_in timestamp. the users who logged in with redmine 2.6.0.stable (we recently upgraded) get a broken one.

Example of https://server/redmine/users.xml

<users total_count="34" offset="0" limit="25" type="array">
<user>
    <id>109</id>
    <login>some_forgotten_user</login>
    <firstname>Name</firstname>
    <lastname>Name</lastname>
    <mail>emailaddress</mail>
    <created_on>2013-06-18T09:16:21Z</created_on>      
    <last_login_on>2014-08-25T12:34:48Z</last_login_on>
</user>
<user>
<id>155</id>
    <login>a newly used user</login>
    <firstname>Name</firstname>
    <lastname>Name</lastname>
    <mail>emailaddres</mail>
    <created_on>2014-09-01 09:21:59 UTC</created_on>
    <last_login_on>2015-02-27 09:51:50 UTC</last_login_on>
</user>

User ID 155, last_login_on seems not to be xml well-formated. User 109 who did not log in since we applied the upgrade is still ok.

What's wrong?