hmm… that is a very short answer Laszlo??

Lilpyro, what I noticed: If a uTrack has a playlist containing songs at different sampling rates, it needs to ‘reset’ the clocks to the new sampling rate as well.
I did not observe any clicks or noises so far, but it does seem to loose the preload functions when switcing from one sampling rate to the other.
That of course makes perfect sense I assume as this would require the unit would be unable to play at one sampling rate and preload a song with another .

So from my perspective, to avoid any issues as you mentioned, delays or issues with preload, it would be my advise to keep all material in a playlist within the same sampling rate.
This simply reduces the risk of potential issues that could occur due to the switching sampling rates during a live show (as you are experiencing now) to an absolute minimum.

To me, always better to be safe than sorry……