OK, this is interesting.
My usual chain is WiiM Pro -> coax -> DAC -> preamp -> monoblocks -> speakers. Or preamp -> headphone amp -> headphones.
My earlier testing was with the above. Tidal Connect failed on this setup.
So as part of the process of isolating the problem, I sidetracked the external DAC, so the chain was WiiM Pro -> RCA line out -> preamp -> monoblocks -> speakers. In this configuration, Tidal Connect gapless absolutely worked with the same test content.
So something odd is happening with the digital outs (or at least coax; didn't test Toslink but they're both S/PDIF). I have the WiiM set to fixed volume and no equalization, so as pure and unencumbered a bitflow as possible. So now the question is are we going to see Tidal Connect gapless failures with all downstream DACs or only some of them, and if the latter, why? If the former, I'd surmise WiiM is doing something odd that disables gapless on digital connections to downstream devices. Unfortunately my only unused DAC is buried in my garage storage so can't do a quick test. And frankly, I'd want to test with 5-10 of different types and from different manufacturers to isolate the problem further.
Thoughts, anyone?
P.S. The WiiM Pro's DAC sounds pretty crappy compared with a modern external DAC. Reminds me of how yucky the DACs sounded in early-2000's AVRs. Thin and fatiguing. The phrase "AM radio" crossed my mind while I was listening.
P.P.S. This would be a good thing to figure out quickly since Tidal, with its pretty significant announced price drop, could be seeing a pretty good influx of new subscribers after April 10th. And many of them could be using WiiM devices as streamers.