Redmine

We're talking about nested sets here, can you please include lft and rgt in your query?
If you ORDER BY lft you already have the basic hierarchy...
SELECT id, parent_id, root_id, lft, rgt from issues WHERE root_id=53 ORDER by lft

Is this what you are requesting? Here is the same query with lft and rgt included, ordered by lft:

select id, parent_id, root_id, lft, rgt from issues where id in (19547, 19121, 19099, 18966, 18956, 18825, 18572, 17887, 17799, 17795, 17601, 18532, 20011) order by lft;

select id, parent_id, root_id, lft, rgt from issues where id in (19547, 19121, 19099, 18966, 18956, 18825, 18572, 17887, 17799, 17795, 17601, 18532, 20011) order by lft;
 
+---------+------------+---------+-------+------+ 
       id    | parent_id | root_id |   lft    |   rgt 
+---------+------------+---------+-------+------+ 
  19547  |   19925   | 19925 |   81   |   82  |
  19121  |   19925   | 19925 |   83   |   84  |
  19099  |   19925   | 19925 |   85   |   86  |
  18966  |   19925   | 19925 |   87   |   88  |
  18956  |   19925   | 19925 |   89   |   90  |
  18825  |   19925   | 19925 |   91   |   92  |
  18572  |   19925   | 19925 |   93   |   94  |
  17887  |   19925   | 19925 |   95   |   96  |
  17799  |   19925   | 19925 |   97   |   98  |
  17795  |   19925   | 19925 |   99   | 100  |
  17601  |   19925   | 19925 | 101   | 102  |
  18532  |   19925   | 19925 | 103   | 104  |
  20011  |   19925   | 19925 | 105   | 106  |
+---------+------------+---------+-------+------+ 
13 rows in set (0.01 sec)

Maybe this relates with #11319.

I agree, it could be, and likely is, related to #11319.

I fixed this one occurance by manually updating my issue 19649 and setting the value of rgt to the value of lft +1. Now both of my issues 19649 and 19925 render correctly.

I can't document for sure how this happened but I suspect that at one time:

19649 had several sub-tasks associated with it
those sub-tasks were moved to a different parent task
19649 was also added as a sub-task to this new parent task

issue 19649 didn't get updated to reflect the loss of its sub-tasks