OSC output is one of those monster features that is hard to maintain and even harder to debug. We're considering full Master/Slave sync via OSC to be currently broken, and it's unlikely we're going to fix it in the 5.x release cycle. We've squashed a few minor bugs related to it squashed during minor point updates, all in all it's too much of a behemoth to take on.maybe some one of the resolume developers would know the answer to this issue.
Even in its current state, the amount you can get done with OSC is staggering, as for instance Ravensc's Enter app shows. 99% of it works, it's just missing the remaining 1% to make OSC Master/Slave reliably. It feels like a shame to axe the whole feature because of that 1%.
If you have a specific set of steps to recreate a specific bug, we'd love to see it. We may not get round to it right away, but the more problems we know of, the better.