Issues with starting screen sharing in custom agent app

[alexgurr]

In the Amazon Connect agent workspace, the start screen sharing call (which uses startScreenSharing on the contact) starts a "screen sharing session" which triggers a connected customer facing chat widget to be able to share screen, as well as grow to focus sharing content.

Here's what the share session looks like on the chat widget:

For some reason, whenever I use this API in my custom agent app, i see a connect log that says "screen sharing successful" but get no callbacks for any of the event handlers (onScreenSharingStarted etc.). The customer widget doesn't change and they cannot share their screen. The agent can share content through chime, but this seems to be standalone from connect.

Open to ideas! Is this related to #944?