Just to explain further the reason between clock switching. Look at all the sampling frequencies: 768/705.6/384/352.8/192/176.4/96/88.2/48/44.1kHz - they all have 2 common fundamental denominators - 44.1k and 48k. Every other frequency is derived by multiplying these fundamental frequencies by an integer (2, 4, 8, 16). Clock is very important in order to have low-jitter performance, and the frequency is cleaner when you multiply it by an integer rather than a fraction to go from 44.1 to 48 (fraction requires multiplication and division).
Many daps use 2 clocks/oscillators on the board, 44.1kHz and 48kHz (femptosecond high precision in case of DX200). When you switch between the songs with a different sampling rate (44.1kHz vs 48kHz or their multiples), the hardware needs to switch between these clocks. I mean, literally, you have some kind of a mux with both clocks going in and a select bit that switches from one input to the other. That switching should be fast and transparent, but it's currently not since you hear a pop when switching between the songs. Hopefully it will be fixed soon.
The problem you described before is different, you are playing high res files and during playback go to a folder/album/file list and scroll fast up/down when you hear pops, That could be related to some buffering issue. In theory, dx200 has a multi-threaded processing (multiple cores handle multiple functions at the same time, playback, browsing, etc). I will try to recreate it once i get home. Btw, do you have gapless on/off when this happens? Wonder if it makes any difference when gapless is disabled since with gapless it usually reads ahead of time to skip the "gap", and perhaps something is getting messed up.
Actually it is so random that I cant predict it. Some times it just play smooth. But sometimes is pop clicking very often out of blue.
I am always gapless off.