Product switching category and language error message after upgrade

[minh]

After upgrading from 12.4 to 1.2.5 hyper links (for anchor and for pop-ups) in the product description no longer works. I get the follow error message whenever I try to edit the texts in product descriptions:

3 errors

the field description (English (English)) is invalid
the field description (Français (French)) is invalid
the field description (Svenska) is invalid

I get the error message when re-saving products that has hyper links in the product description text. After the error message, the product has jumped to the first product category (always the first after Home).

The French and English translations were empty before upgrade. After upgrade they suddenly have the text I have previously imported as CSV.

Why does the product jump to a different product category after the error message?

Why does hyper links not work after upgrade?

And why does hyper links cause the error message?