Teams live event audiodrift issues.

We are using an atem switcher (1080p50) with an xr18 feeding an analog line to the Atem. With a local recording direct from the Atem, I'm in sync. But when I output to teams live event (rtmp)via a webpresenter the audio will drift. When I use the same setup to stream to YouTube we don't experience any drift. What's the issue here?