rncbc.org a.k.a. Rui Nuno Capela

Okay, figured the woof thing (woof is a sound you get when the fade in occurs on a base drum :)
It does not occur anymore when you are playing a tune without a loop. As soon as you turn loop mode on - woof comes back. And when you turn off the loop mode - in fact, it would still woof for some time, but then go away. Occasionally, I would get a woof even in non-loop play mode, but very rare and I found no pattern.

The loop playback is not very good - it has a small crackling sound when it restarts. If you loop a midi clip, you would get weird results. Sometimes it would miss first notes, so if you loop a chord, it might not play it at all - as if the playhead has skipped the notes and so they do not sound. Next iteration - it would play it okay. But in general the loop mode playback is not seamless.

Hope this helps. If more testing is needed concerning this, tell me what to do.
;)