The problem here is down to the degree to which the form generation has divorced itself from the normal views exposed form generation process. Modules add process callbacks and the form goes through a lifecycle that manipulates the values and content in ways that the current code does not replicate. I've attempted to refactor this to get us closer to a solution that replicates what Views does when generating this form.
Needs review
1.0
Code
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It's likely this issue predates Contrib.social: some issue and comment data are missing.
I had the same issue. After applying the patch in #16 the exposed filter completely disappeared and is no longer available.
I couldn't get the patch in #2 or #7 to apply - but haven't had time to dig into it.
Using viewsreference_filter 1.0.5 and core 10.2