Comment 5 for bug 1977662

Yes, this is the symptom.

The root cause seems to be the engine playposition:
if passthrough is enabled, loading a track queues the new position. only after disabling passthrough the engineDeck will process the buffer and processSeek() is called.
Thus, with passthrough kInitialPlayPosition persists (std::numeric_limits<double>::lowest()) which leads to confusion down the line.

I could add a workaround, probably considered a hack, but it definitely solves the GUI freeze / crash.
https://github.com/mixxxdj/mixxx/pull/4787