Page Check in issue

Is this a Portal Engine or MVC site?

Where did you try to check in... where you updating widgets or entering form fields?

Yes, this is Portal Engine. Kentico 11. I want to check in a page that I have edited a field in the form tab.

So I tried to do the same in test Kentico site and it works.

Also another strange behavior I found in the page form tab. I am trying to update the Product name field in the form tab of this event instance page, it saved correctly, and then checked in fine. But then when I refresh the page, the Product name still shows the old value. So I then checked in the database COM_SKU table, indeed the field SKUName remains the old value, didn't gets the updated value. But all other fields in the product form like price, description, etc all updated correctly. I am very puzzled...

thanks for helping me

I assume this worked fine at some point - what was changed recently? Not only in Kentico but also in the environment - e.g. server updates, .Net framework, etc. Also, if it works on the test instance, what is the difference? Is there any custom code, custom event handler or anything else which may be triggering any code when saving/checking in the page?
Are you using workflows?