So don’t do that, then!
UART1 is specifically an AT Command port by default - so, if you flood it with invalid data, you should not be surprised when Bad Things Happen!
No, that’s not true - I’ve seen this in earlier versions.
eg, see: DOTA is sucessful but system restarts twice - #8 by awneil
You need to either switch the UART to FCM Data mode, or use the Raw access - or find some other way to stop the invalid data!