Replies becoming new tickets after migration

[mwpnl]

Hello,

After a update that went horribly wrong, I had to install a clean version of OTRS. I then replaced the (new) database with a backup, containing all the previous data. I also changed back any configuration changes that I've made in the sysconfig.

However, I now find that, for old tickets, if a customer replies, a new ticket is created. (old = from the database-backup)
With tickets that were created after the new install, this problem does not occur (e.g. replies are added to the ticket as an article)

I checked the ticket hook and systemID and they seem to match the old configuration. Any guesses or ideas what might cause this strange behaviour?

[mwpnl]

The documented systemID actually was different from the systemID we used previously. After looking in the database and changing it to the proper systemID, the functionality actually works again.

Sorry for the bother!