Have now just had the 2018 draft in my game and the issue is definitely persisting for me. The transactions log looks all fine and normal...
But then when you go into the contract details of various players.....
As a result a few (but not as many as before it seems) starters or bench players with significant trade value have simply been waived from their team's 40-man to make space for these guys and subsequently claimed.
What can be going on in my game which didn't show up in your test?
(Sorry about the large screenshots, I couldn't work out how to make them smaller)