FW 7.60 - strange HR readings? (HRM-Run)

Today I did my first run after upgrading to FW7.60.

I noticed right away that my HR seemed quite high compared feel and pace. I verified that the HRM-Run was actually connected (which it was), and after a few minutes I «concluded» that it couldn't be caused by just a bad day as the reported HR couldn't possibly be correct as it didn't match my perceived effort or pace.

Throughout the whole 10km run the HR remained about 10-20bpm higher than expected/felt. According to the run report I basically did the whole run in zone 5 (based on LTHR), Training Effect 5.0 with 3,5days recovery... Not very likely as I wasn't anywhere close to pushing...

Not a big deal in itself as I prefer to use Stryd power to monitor intensity during runs, but the bigger issue is that false HR throws off all the FirstBeat stuff like Training load, effect, status, vo2max, recovery, calories etcetc... 

Anyone else seeing this?