Don't know how true it is, but I saw on Reddit someone said that the betting wasn't on yellows for individual players, but yellows for the team as a whole. Could very well be that Clayton was unlucky enough to get a yellow in the wrong games which put him under suspicion.
Edit, looking at the stats on Transfermarket this is the yellow history for the players over the last three seasons:
Uli:
2021/22: 1
2022/23: 1
2023/24: 4
Baccus:
2021/22: 1
2022/23: 6
2023/24: 7
Clayton:
2021/22: 2
2022/23: 2
2023/24: 5
So the current season is a big outlier for both Uli and Clay which is either evidence or could make the authorities think there is a pattern when he's just had a pretty ill disciplined season.
Edit, looking at the stats on Transfermarket this is the yellow history for the players over the last three seasons:
Uli:
2021/22: 1
2022/23: 1
2023/24: 4
Baccus:
2021/22: 1
2022/23: 6
2023/24: 7
Clayton:
2021/22: 2
2022/23: 2
2023/24: 5
So the current season is a big outlier for both Uli and Clay which is either evidence or could make the authorities think there is a pattern when he's just had a pretty ill disciplined season.