Not sure if it's related to the latest iOS, but since I updated to 15.0.2 I noticed an erratic behavior with my iRig Stream on iPhone.
The signal is detected, and after a while (some minutes) it is not detected anymore, the level LED becomes fixed blue and the streaming app does not receive any sound. It happens particularly on Instagram.
To remedy, I unplug and replug the iRig, shoot a video with the Camera app to ensure signal goes thru (light moves to green/red as usual), then go back to Instagram. But this doesn't work every time.
I also noticed on the top left a flickering orange microphone icon, as if it was switching between mic modes very fast. Maybe the new Mic Mode function is what prevents the device to function smoothly.