Hi Simon,
I've two problems with ZAP 2.8.0 before disable HUD:
1. Incorrectly process request from SoapUI. ZAP lost ports and sends request to 80 port, instead of 9000
2. I've debuged Apache NiFi (server application) using ZAP and NiFi can't switch to https.
Disabling HUD resolve those problems.
I think, it should be warning about this behavior.
BR, Leonid Vygovskiy