I'd bet it was a traction issue, but now I'm thinking twice about that. I'm trying to remember where I felt a bit of bogging - it's starting to fade on me - but my impression at the time was traction. I rarely had to crank and recrank the wheel.Facelift fk8 also shows oil temps, calculated from other measures since it doesn't have an oil temperature sensor. It's probably calculated from oil pressure, which is affected by an oil cooler or a different oil viscosity. Should the fl5 have similar calculations, it might be interesting to add a real oil temperature sensor in a future sandwich plate. Otherwise you might not know how accurate is that gauge after mods.
Thank you for the detailed response. What were your tire pressures? You mentioned the nannies in your exits. That seems like the understeer assist acting up, unless it was a traction issue.
My tire pressures on the Falkens started at 28 cold and got to 36-37 hot, always taken after a nice cool down lap. The Michelins started at the same place but even on a damp to wet track, got up to 39 and I wasn't even pushing that hard. I probably was overbraking that day though so that might be a part of it. On a hot day, I'd probably start them at 27 and knock them back after first 8 laps of first session.