Redmine

Hello,

we have a Redmine installation (1.2.0) with multiple projects and ~740 issues.
Suddenly creating new issues leads to an internal error.
Investigating this I found that these issus had been created with NULL values in the "lft" and "rgt" columns.
This behavior happens for every newly created issue no matter in which project or if it is created as a subtask.

We have a number of plugins installed, but didn't perform any changes in that regard since a few weeks.
Does someone have any idea where this behavior might originate from or where to start to fix this?

Thank you a lot