Observium error in contacts after upgrade

Dear Observium team,

when updating my instance to the latest version using svn up and then ./discovery.php -u where everything looks perfectly fine I'm then seeing the following thing under https://observium.company.org/contacts/.

Are you having an idea why that happens?

I also did a svn revert -R . but no changes were detected locally!

Many thanks in advance and best regards,

Peter