HRM-Pro plus reboots watch when trying to start an activity

Hello,

my Hrm-pro plus works greatly when I'm using it for running, walking etc, no complaints. But when its connected to my watch and I try to start skiing activity, the watch reboots almost instantly. After rebooting everything works normally until I try to start skiing activity again with the strap connected. Skiing activity itself works fine when used without hrm. I have a Fenix 7x sapphire solar edition. When the skiing activity is chosen, gps meter wanders a bit and then it reboots. That's the only thing I can say looks unusual.

Is it possible that HRM-Pro plus doesn't support skiing activities or is this some software issue?

I have checked both the HRM and fenix 7 that they are up to date with latest updates.