My VIM2 is an earlier version, 1.2 I think. You have the later version(1.4)? Maybe the difference is there, they use different fans. Keep in mind, this Android Pie is a preview release. You may want to post the issues over here and let Terry know. Hopefully the issues can be resolved in a subsequent release.
FYI If I recall, the fan worked in both superceleron’s SCV-1 and SCV-3 ROMs.
The ROMs by superceleron are not based on Android Pie. I think they are based on 7.1
Until the issue gets resolved, as you have found any fan you can direct towards the heatsink should keep temps under control. To get through times like this, I often use a generic 12volt BB fan run from the GPIO’s 5 volt pins. It is adequate for cooling, and though it runs all of the time, as a 12v fan running on 5v, it is pretty quiet.