I have the exact same problem, I thought it was an admin rights problem since i noticed it after upgrading a few of my users to Administrator, and it’s only some of their posts i have problems editing.
Just to be clear, it’s afaik only the Product short description which does not update when i either save as a draft, or publish/update the product post. (It just reverts to previous text)
So far i’ve tried;
Duplication of the product
Removing all variations
Changing product type to single product
Changing the permalink
– Nothing has helped.
*Hopes* someone out the knows the answer to this issue, – I will update if i find the solution.