Apple Music Lossless playback sometimes requires iMusic restart

I just subscribed to the Apple Music Trial to check the new Lossless option, which I'm using on my 16" MacBook Pro connected through Thunderbolt to a Focusrite Clarett external audio interface.

It mostly works, and it's clearly lossless, the difference using my Genelec monitors is obvious, and I configured the audio card at 192/24, so it works just fine with hires tracks too.

However, sometimes the stream just doesn't start as lossless, even for songs I already know are in lossless format and the *album* info shows the Lossless logo. When this happens, it seems iTunes gets stuck in "lossy" mode, and requires a restart, so the same song that played lossy in the previous session, would now play lossless after a restart.

If I check the Information about a specific track when lossless stops working, the "File" Info tabs reports just "Stream". If I restart iTunes, the same song will now say "Apple Lossless", in addition to report it as a Stream. The player bar for the track doesn't show the Lossless icon instead, but the album info always has the Lossless icon.

This seems to be triggered by switching to a different song, even in the same album.

For example:

Let's say I'm playing "Money" from The Dark Side of the Moon in Lossless. All lossless icons shows up normally, and it sounds great.

If I let it continue to the next song automatically, most of the time is still lossless but, if I switch to another song manually, let's say "Time", it reverts to lossy, with a clear drop in both output volume and overall audio quality. The lossless icon in this case disappeared from the top player window.

To fix this, I exit iTunes and restart it, go back to the same song that played lossy, "Time" in this case, and Lossless is back again!

Note that, not a single time I ever had sound "issues" with the external audio card, like dropouts, noises and such. It always plays everything flawlessly...it simply loses Lossless when switching through songs across the same or different albums, always requiring an iTunes restart, which always fixes the problem, provided the affected track *is* offered in Lossless format, of course.

Switching a song doesn't always disable lossless playback at the first try. Sometimes it can switch 3-4 songs and keep playing lossless but, once it disable itself, there's no way to restore it on *that* song, but an iTunes restart always fixes the problem.

I hope to have provided enough information to check about this issues, which makes listening to Lossless music very annoying, especially considering a Mac with an external audio device seems to be the most compatible way to enjoy Apple Lossless.