I just talk with them. They have strict rules about patch and upgrade. These are done inside week and never even on Friday. Last patch was done week ago. My problems started on Sunday, so this TB1.5 was working with patches almost week. But error is still present and I can't find anything in log files and this TB 1.5 is test site. I was trying to import CSV files, there are something like 10 000+ products. So I try from zero. If error is gone then it was probably something with databases, they're too big or there is something that is not accepted. I will not destroy current thing, just making new one.