The internal AFC of the ADF7021 does not work correctly with pulsed TDMA signals as used by DMR. In fact the chip struggles to lock on these signals with or without AFC. Hence the need to fine tune the frequency to minimise the errors.
You may want to change the orientation of the 2 antennas on the hotspot, because it stands those 2 antenna are oriented for maximum coupling of the Tx to the Rx.