DTC not working?

[advr6]

when riding in the rain yesterday the bike fishtailed in both Rain and Road mode when trying to pass cars with moderate throttle application.  I rolled back on the throttle before any DTC light came on (probably 2-3 secs) Bike was upright and not on painted lines etc.  tires are bridgestone T30s with about 5000kms on them.  The DTC was turned on (no light on the dash)  but the DTC light did not come on during the fishtailing indicating that it kicked in.

GS-911 found no fault codes

Question:  Is that normal or should DTC suppress all fishtailing in Rain mode? 

I thought you guys in the UK should know given that you ride in the rain a lot  :).

thanks