I have mixed Nanos, Pro Minis, ESP8266 and Unos and no problem. I do however have mixed NRF24L01 and NRF24L01+ due to a bad AliExpress saler that stated he sold NRF24L01+ which in fact were not the + version. So I have set my baudrate on all nodes to 1mb.
In order to be helpful we need the log on the Uno.
No, it does not recover.
The Problem is not easy to debug. I now want to build a serial gateway. With that, I am more flexible to test. Maybe to run MySensors on a second raspberry pi with a standard Home Assistant HASS-Os image. Or I check the MySensors network with MyController.
At this moment i run the whole system on 64 Bit raspbian, with HA in docker, which is a little bit experimental and i had to fix some lines in the ethernet gateway to compile it for 64 bit. So this is experimental, too.