Problem with display of 2-disc albums

[nimonic]

I am using dBPoweramp Mac version and a Synology DS416 with DSM 6.
Both discs of a 2-CD album appear to rip successfully, with the same album art etc. When selected on the NAIM app on my iPad the first disc is displayed correctly, but the second is shown correctly for a second, then shows a completely unrelated album cover and title, and track 01 as >>Disc 2. Please see screen shots attached. This has now happened several times with 'double' albums ( I hesitate to try 3 or 4 disc sets!). Has anyone else seen this fault?
Regards,
nimonic