The simplest reason is that you can’t record something that you didn’t play yet or that you already played. If sync start is on, and you start a new recording after the sync start point of that song part, the Aeros can’t fill the part that you already played but didn’t record, it must wait until the start points is at the beginning again. If you want the Aeros to immediately start recording you would need to be set to sync length only.
That being said, I’m sure that there are some issues there right now, as that is something we are going to be looking at next. Undone logic is still not perfect, so stay tuned on this but it’s coming very soon.
This is only if you start the recording after the loop forgiveness zone (300ms after start point), this could also cause some bugs still. It’s the corner cases we need to look at.
One cool thing that we’ve recently added is the ability to undo a track while recording it and making that a much faster process.