Masked Attribute Players disappearing

Something a bit odd has happened in my game and I wondered if it is a bug or if anyone else has come across it. Not a gamebreaker but a bit weird.

I had a player search set up for a striker with a few attributes checked and there were various players available on a free who had partially hidden attributes. I realised I had done something wrong within my game so took it back to a previous save (on the same day) prior to me setting up this player search. Having re-set up the player search again, all of these players are no longer coming up and having looked at one as an example, some of his attributes that were previously visible are now masked.

I don't have any scouts employed so it can't be a case of country / region knowledge developing but even if it was, as I say, this activity is all on the same game day.

Any ideas?