First notes are out of sync in Midi clocked slaves

Hello all, I posted this question at the end of my last thread “Reaper to Renoise” but thought it might be a good idea to create a new thread for it as it is a totally new topic. If this is a problem, my apologies.

I have several external drum machines and synthesizers, each with their own internal sequencers which I use to sequence them with. They are slaved to Renoise. When I press play, the very first notes either don’t play, stutter, are jumbled up and out of sync, delayed… then strangely get into sync for the rest of playback. This happens about 50 percent of the time.

Is there something I can do to fix this in Renoise?
What’s going on here? I’m 99 percent certain it is a MIDI problem, as I have no such problems with audio. Could it be a problem with my relatively cheap audio interface?

Please help! This is an annoying problem