Haven't heard of this issue on this engine before (but it's a relatively
new engine, so that doesn't really mean much).

Typically waiting for tech support means one of two things:
1. The technician didn't wish to hold for the next available tech support
staffperson and left a message. Returning messages is very spotty. For
this reason, I always hold.
2. Tech support needed to contact engineering for some reason. This is
rare, and an answer is usually forthcoming within 24 hours.