Hi,
Thanks for the access.
I think I was able to reproduce at least one of the issues consistantly on your website:
- I select the "Disney Frozen 2" tag in the product "Disney Frozen Alu Trinkflasche, L35-755734"
- I save the product once and the tag is properly added and I can see it if I open the product again
- I create a new tag ("Disney Frozen 3" for example) by typing it directly in the input field of the tag system in the product edit page of that product and save the product
- when I open the product again, instead of having both tags, I get no tag
So next, I tried the exact same process in a Joomla article on your website, and I got the exact same problem. However, on a Joomla article, HikaShop is not involved at all. So if you already have the issue in Joomla, it's no wonder you get the same problem in HikaShop since HikaShop uses Joomla's tag system.
So then I looked online for that problem and I found this page:
issues.joomla.org/tracker/joomla-cms/35649
This looks strangely similar to the issue I was able to reproduce on your website.
It says that it comes from a migration which changed the structure of the table #__ucm_content in an incorrect manner.