All attributes dissapear on product save

There is some serious problems with latest version. If you go into a product (product editor) and just save the product ALL attributes are deleted. It seems to work ok when you have re-instated the attributes again, but all first-time edit of any product when on version 7.6.0 removes all attributes.

Tested on 4 different websites on 2 different hosts and all have the same issue, attributes dissapear on first save.

Brgds
Rune