I kindly suggest to check if the issue has been reported at https://dev.tiki.org/Wishlist
If yes please post an update here.
If you can’t find a ticket on our wishlist, please open a ticket at https://dev.tiki.org/Make-a-wish.
Create an instance set a sample there. (paste the link to the item here)
That will be great to have real life test to understand the issue.