I have been discussing your case with Roland, the test manager at Naim. I’m just getting hold of your support tickets so we can start the conversation with Tidal.
The issue you are having is not wide spread at all, unlike the last Login Error issue that all iOS users were getting. Hence, we need to ensure we give Tidal precise account related information.
Based on what you describe it sounds like you may have your Tidal account details on another device. On Tidal it can only play from one device at a time and if another device is used (even if its just downloading stuff in the background) then it will mean the music will stop playing after the current track.
1 Play Tidal music on Atom. Track 1 is playing
2 Another device X, plays / downloads a different track from Tidal.
3. The action of 2) means Atom will stop at the end of track 1, as device X is considered the owner of the active playback session.
Worth checking. If unsure, change your Tidal password and only update the new password on your Naim product.