Ah, I have a feeling about what could be the problem.
You have regular pen and select, not iN versions if I caught correctly?
Kill the BT on pens and selects. If I remember correctly, long press on green call button for like 7 sec, until you see orange light. And then don’t activate BT on pens and selects.
If you turn on bt on mic, HA will go insanely crazy switching on to autosense every second or so. At least that’s my experience and from one other user here.
Also, pairing is done only when you want to pair for the first time or you want to change which one is your main one. Like when you want to have select as table mic and pen and another select as lanyard, then you connect the one you want as table first with HA, but others you connect with that chosen select, not your HAs.
No unpairing needed.
But after rereading, I think what happens is that your phone gets some notification, even without sound, and that triggers the HA to switch to streaming mode, and when nothing happens, they go back to the default, which is autosense.
Oh and when you press connect key for 3 seconds I think you basically disconnect the select.
Try just ordinary click, not ‘press and hold’. You know, ‘click and remove your finger’ . Blue light will start immediately blinking.
‘Press and hold until the light’ is only for disconnect.
I know that I described now several things, but I tried to cover all findings I have, since I’m not quite sure from your descriptions. I mean, tech support would be easier on video call so we both can see each step than by writing on forum, but we have what we have
Try first thing with fast click I’ve mentioned the last. Test what happens.
If that doesn’t help, then try disabling bt for calls and media (so, not kill bt on phone but disconnect that bt device, but only that not LE marked ones).
For non iN mics definitely kill the BT on them by long click accept call button or whatever you have to do for regular select, I’ve read manual only for regular pen.