Shopify metafields disappear from facet list after reindexing

I have a Shopify integration with custom Metafields that I’d like to use as facets.
Adding them under the “Metafields Indexing” configuration section in Shopify does not work, i.e. they are not getting exposed as facets in the index.
I can make this work by logging directly into Algolia and adding them as facets. However, they disappear once I trigger a new reindex from Shopify, making this solution unstable.

My metafields follow this naming pattern: “meta.my_fields.origin” etc, and that’s how I add them in Algolia.

Can you confirm these are product metafields? Per our docs, only product meta-fields can be used as facets:

Yes, I believe so. I’m looking at the product detail admin page (/admin/products/xxxxx), and under the “Metafields” section is the info I’d like to use for faceting.

That definitely seems like a product metafield.

Normally metafields should be exposed to be used as facet in Shopify if it’s available in the dashboard.

I asked around and one colleague mentioned having the same issue for a client before. It seems the Shopify extension won’t expose a metafield as a facet if it’s only on a small set of records. Could this be the case for you?

They resolved the issue by adding the metafield to more products and performing reindexing.

I can confirm that this keeps happening regularly whenever we trigger a reindex from the Shopify side (or even add or remove a metafield).
Can you escalate this bug to your product team? It’s keeping us from going paid and relying on Algolia for our search, because it means most of our filters might just break silently at a whim.

Thank you!