Hello guys again!

I do understand how meshtastic works, that buildings, trees may cut the signals and the higher the better etc.
Yet, in my home, leaving my device l1 tracker pro at a specific place, gets lots of traffic, and I receive more messages than before. Since then I always leave it there. Now my question is, how come I can receive messages but not sent, especially when channel utility is 7 or even 10 percent? Do I miss something?