setting mode '-' breaks network

[a-allard]

With a SAMR21 module running (using PA18 & PA19 for uart pins) once mode is set to - the SAMR falls off the thread network and will not get back on without a hard reset (either from the reset command or a power cycle) The terminal works fine and it acts like it should be connected but it does not send or receive successfully. An NRF52840 operates as expected staying connected to the network and still sending and receiving.