Duplicate screen doesn’t work with teams app + other observations

My test setup:

Windows 10 Laptop with teams app and external monitor.

iPad Air ios 12.4.2 with teams app

Situation:

laptop and iPad join team video conference

ipad shares photo

What happens:

Video streaming on iPad stops

No dual screen on laptop with external monitor

with reverse situation (laptop shares photo), the same situation: video streaming stops.

Other observations:

During the video conference I can only add ‘known’ contacts (only AD contacts).

Video/Audio latency is more observable that with competing video conference systems.

Video quality is less than competing video conference systems.