qt.protobuf: No serializer found for type QList<...>

This failure+crash only happens in windows, and was observed in 6.8.2 so I upgraded to 6.9.0 and still see the same problem.

Looks to me like there's a field type that isn't getting its serializers registered. I have confirmed that this behavior does not occur in 6.8.0.

I am compiling the libraries separate from the application, and following the instructions to help cmake get the right stuff linked in.

I suspect I haven't provided enough information for action; I'll maybe work on a minimal example later today.  If there's something else you need to know about my environment please ask.