MIDI note not triggering, other odd anomalies

[monnomme]

I just picked up a Novation Peak and am trying to compose some music triggering the synth via Ableton.

I'm trying to record the MIDI I've written to an audio track, but every time I reach a certain point, a particular note does not sound. It's not muted. I delete the note and rewrite it into the piano scroll, and it plays perhaps one time only. I keep trying to record, but this particular note won't sound.

Also, even though there is no variation in velocity on the MIDI track, when I get the end of the sequence some notes are suddenly swelling in volume for no apparent reason.

Any of this sound familiar? I've tried restarting and several other things, but I keep experiencing these annoying glitches and I can't actually proceed making the most basic music. And just now, trying to rerecord once again, suddenly the two MIDI tracks (Peak and my drum synth) are not sounding at all, even though no settings anywhere have changed.

Thanks

[monnomme]

Working on something else tonight - no synth at all, just stock VSTs - and encountered more MIDI mysteries. Simply trying to copy-paste very basic basic bass loops and they would go out of sync with the other loops very quickly. I finally had a brainwave to try adjusting the buffer. The setting was some low figure, and once I turned it up to 512, everything worked as normal. Will have to try this with my earlier project with the Peak issues and see if that solves anything... SO, based on my original post, does a buffer issue sound like a typical newb road bump?