OK, I will answer here. This is the problematic part, copied from CG forum:
11.04.18 18:38:42 #1 C42P53 ekspanzi - PB not saved : Lap not clean...
11.04.18 18:38:42 #1 AIRW - new FX2 PB by ekspanzi: 1:38.41 (-0:00.80)
PB not saved but AIRW accepted? Shouldn't it be the other way, AIRW in fact more strict than local PBs? No, not really.
The AIRW PB is done with a custom car. AIRW will accept ANY lap time as a new PB in a supported custom car, as long at it has all required split times as well. If works just like LFSW lap times, everything is accepted, no checks. The strict AIRW checks are applied only for good/best online laps, in standard and custom cars. So, for personal best anything is possible. For good/best lap strict checks apply.
As for PB not saved because of unclean lap, there is OffPath value in TCD file. This value makes the standard (strict) path wider in both direction by the specified value in meters, and if CheckRacePath is true in SRV, only PBs done on this (wider) path are saved. So, probably, the OffPath value is set pretty low and there was a small lag or visit too far outside the proper race track, so the PB was not stored locally.