I’ve been using a couple of original reach rtk units, upgraded to 2.18 and got caught out by the 2.18 3DR radio issue.
Tried upgrading to 2.21.1 to see if it was resolved but doesn’t appear to be. Can’t say if it exactly the same cause as setting UART serial output in Base Mode sometimes hangs (spinning busy circle doesn’t go away). After rebooting the serial output setting seems to have stuck but I cannot receive corrections at the rover.
I also encounter the zero AR and GNSS Select under RTK settings are lost after rebooting.
Good luck bug fixing.