I think there is a lot more movement from Orthodox and Catholic churches into Protestant churches than most people really realize, probably more from Catholic to Protestant than Orthodox, but it is still there. It is more obvious in Liturgical churches like Lutheran and Anglican churches as those tend to attract lapse or minimal Catholics due to the similarity in worship style. At least this seems to be the case in my anecdotal observations.
I would entirely believe it happens in the clergy as well, unless they make a podcast about it we just don't hear about it as it is not exactly news worthy.
People move into the Orthodox and Catholic churches as well, of course. I crossed the Tiber, and eventually left again. So technically the RCC would have me on the roles still. But the numbers moving into those churches is likely less than the numbers moving out or just leaving the Catholic/Orthodox church all together for nothing or just being inactive in those churches.