not sure if this is gameplay or visual bug, but i think its more of a default directed camera bug during coaching.
i think the HUD is still on Directed camera instead of free camera by default, hence keep switching heroes every few seconds when game is paused? as shown below in clip. would be nice if coach has the option of Player perspective again during live games too.

im not pressing any buttons btw

https://clips.twitch.tv/SlipperyCrowdedClipsmomWow