Prepared statement needs to be re-prepared

We have massive problems with MariaDB freezing with the above error and after hours of googling I could not identify an authoritative answer. This is a production environment that has for the longest time worked just fine, but now that we have set-up some 180 views on the server to relieve computational load from some 50 clients and the corresponding network load we are facing serious performance issues. I would appreciate a lot if there were somebody out there to help me systematically troubleshoot the issue. At this point the only solution I see is to attempt a migration to PostGreSQL or Oracle, but I'd rather avoid that.