Why does my Mac Pro's hostname keep changing to 'HUAWEI_Y6_2019-...'?

My MacBook Pro (running BigSur 11.2.1) now - since I rebooted it last night - keeps showing the host name as 'HUAWEI_Y6_2019-{hhhhhhhhhh}' in the bash prompt. (The hh's are a 10-digit hex string.) The hostname command likewise reports this value. In System Preferences > Sharing, Computer Name still shows as 'macbook' (which is what the prompt used to say). I've tried editing that, then editing it back, and that fixed the prompt for new bash sessions - for a while. Now it has started doing it again. These are not remote bash sessions just bash shells on the local machine. Does anyone have any idea why this might be happening? Or where the value is coming from? As far as I'm aware there's no Huawei hardware on my home network (unless the 'BT' badged hub is really a Huawei box). UPDATE: I have reviewed https://apple.stackexchange.com/questions/30552/os-x-computer-name-not-matching-what-shows-on-terminal but that seems to refer to a remote bash session. That is not the case here.