If (TBC) you’re on a LHR host which is having resource problems, possibly triggering an app issue related to unexpected (e.g. IO issues) behaviours (subsequently causing your app to have a funny turn and peg the CPU), you’re always going to have the problem on that host until the underlying issue is resolved.
AFAIK one key difference between V1 and V2 is that with V2/machines - any given machine is tied to a specific host. With V1 if you redeployed you could end up on another host (“fixing” host-specific problems) - with V2/machines this isn’t the case.
I’ve had a few host-specific issues in the past, threads that may be of interest:
Possible network problem (periodic spiking latency) in LHR/on host 81b8?
Feature Request: FLY_HOST environment variable
Your issue(s) may indeed be V2-specific and/or app-specific, and nothing to do with the host(s) - but it could be worth considering/investigating.