Advanced Search Plugin: Attempts to index many variants twice

[toBeOfUse]

When the advanced search plugin re-indexing job runs, there are many documents that fail to be indexed:

This appears to be because many duplicate variant IDs are fetched while the index is being built, and so the same variant documents are sent to the index multiple times, resulting in the second document failing:

I'm not sure exactly why, but I assume it's due to a redundant left join of some sort in the query builder - maybe it's retrieving two of each variant that is in multiple channels?

[toBeOfUse]

(This doesn't appear to cause any problems with functionality, since TypeSense rejects the redundant variants, but it does cause error messages and slow things down)