Yep, I get you.
I also initially found out it surprising about Fred but I do remember looking at Fred's pass completion stats earlier in the season and they were actually much higher. He's at a tick under 81% now but a couple of months ago was at 83%. He plays it more safe than Eriksen, Casemiro and Bruno so that's why he's higher and he is also worse at progressive passing than all of them (same story for McTominay).
Eriksen probably ranks lower because he does a lot of long balls and switches that don't always hit their target, but he is an excellent progressive passer.
Casemiro had a much higher pass completion at Madrid. I remember when he joined us he was at around 85%, now down to just under 80%.
He obviously makes the odd mistake with short passes, and also makes a lot of long balls like Eriksen and is also a superior progressive passes than Fred.
The story with Bruno is similar as he ranks very highly with progressive passes.
Long story short, at least in our midfield, high progressive passing metrics is inversely correlated to pass completion percentage because of how adventurous with passing our creative midfielders are.