Summary: Search & Discovery filters fail to work properly with translated metafields in non-default languages, despite translations being correctly configured in Translate & Adapt. The issue appears to be related to indexing.
We have recently encountered a weird issue with presumably Search & Discovery.
It occurs sporadically with some products. In all cases we have detected so far it looked as follows:
We had several products with metafields. Some metafields were defined on product variants as well.
Then we visited a collection page that contained said products. In the base language (german) of the store, everything works as expected.
However, when we switched to an alternative language (in this case french, but others had the same issue) we saw some weird behaviors with the collection filters.
At first, we assumed, that we just missed one metafield when translating the store.
However, when we looked up the product in Translate & Adapt, it was already properly translated.
While debugging, we tried changing the translation manually to “our2” and back. Afterwards the issue was resolved.
We thought this was a one off issue and did not investigate further.
However, after a few new products were added and generated the translations, we encountered more similar issues across different languages and with different metafields.
We are currently suspecting that there are some issues with the index that Search & Discovery builds.