Yes we know about MariaBD. We have migrated all our databases to Mysql in order to avoid the problems.
Now we have some other pretty weird issues. For example, on the forums, a member found himself administrator of a section ...
Or I work too much or I...  moreYes we know about MariaBD. We have migrated all our databases to Mysql in order to avoid the problems.
Now we have some other pretty weird issues. For example, on the forums, a member found himself administrator of a section ...
Or I work too much or I have to stop drinking
I have been working on SE for several years and I really do not understand.
We are still investigating where these problems are coming from. I will keep you informed.  

When you say you load the surveys, are you using a plugin named survey or are you using the default poll? 
Are you creating them or loading them from a database backup, inserting into the database?
Are these the same names as the other polls you...  moreWhen you say you load the surveys, are you using a plugin named survey or are you using the default poll? 
Are you creating them or loading them from a database backup, inserting into the database?
Are these the same names as the other polls you made? 
I cannot reproduce this on my test site.   

It's disappointing to see the 'Edit' function has been disabled. Could you not just add a database trigger on creating and updating forum replies that would create an audit log? As it's only for site owners it doesn't need to be pretty.