Pairing Varia Radar with Venu 2 Plus and Edge same time

I have my Varia Radar RTL 515 paired to my Edge 840 (as light network) and I would like to pair radar simultaneosly to my Venu 2 Plus to have vibrating notification.

But when I'm trying to pair Venu and Varia radar, Venu can't find Radar device, neither as light nor radar.

Any idea, what is wrong?

Thanks for help.