Same for me on both PC and iPad.
I set full 20 plays in CUST35 via iPad, got the error on each. Pulled up on PC, all 10 Off plays show but only 8 of the 10 Def. Selected 2 more on Def on the PC and got the error.
In CUST 10, only 7 Def plays are showing, same as yesterday. I set 3 more and got the save error.