The instrument plugin impOSCar2 (GForce) seems to be misreporting CPU use when using certain patches (e.g. Servolan; not sure what in the patch causes it) when playing a note (Reaper shows it as 2000000%+) which seems to be the case in Reaper 6.26 (I also checked in a 6.21 install)
It doesn't affect a previous Reaper version 6.11 where under the same patch it reports a more expected value, was there some change in how CPU usage reporting is done?
I've reported it to GForce already.