I noticed this too.

This seems to be a side effect of a change made to ensure that only fields that should be updated are changed.

It appears that in the bug_update pages, the fields are displayed if the "display_update" or "require_update" flags are set. If the "display_resolved" or "display_closed", aren't set, they won't be updated. The work-around would be to set these flags, or to use the "Change Status to:" button to change the status.

This is surely confusing. Even with a workaround. If seems that if one were going through an update using the update form, all custom fields set with "Display When Updating Issues" should show and be updateable, whether "Display When Resolving Issues" or "Display When Closing Issues" are set or not. Those latter flags seem to me should only apply when going through a "Change Status to:".

Fixed in CVS.