Can't edit or add products Prestashop 1.7.1.2

[DimpZ_1]

Hey guys, I'm facing a big problem with my prestashop 1.7 installation. It was running ver.1.7.0.4 after that i upgraded to 1.7.0.5 and now it's 1.7.1.2. Recently I faced problem related to adding and editing products in back office. Even though I edit descriptions, price and product name I save it and changes does not appear in store. 

I've been using bypass solution and edited products using prestools plugin. This way everything works fine. I looked for this and some people say it could be related to translation problems. I disabled all languages except one that store uses. 

What could be the reason of that kind of problem. Please help.