This is a strange problem, we have not experienced such problem yet.
Please check that is there any field on product edit page that is saved? For example, if you modify the title or the description of your product, is it saved properly?
So only the tab titles and tab contents are unsaved?
Please let us know the result of this test.
What is your WordPress language?
When we get the requested information, we continue the problem-solving.
Thanks for your collaboration.