I managed to get Grim Reaper to pop for me by staying in the same server until I got 30 kills. Edit: And Hoist the Flag, I previously had over 10 spread across several matches, this time I stayed in the lobby and got it after the 10th flag.
There was a near identical issue with BF1 a few years back.
https://answers.ea.com/t5/Technical-Issues/Trophy-glitch-battlefield-1/m-p/5648066#M2429
The problem in this case, of course is, getting 150,000 score per class, then 500,000 in total.
Because back then you could work around the issue by staying in a server and ranking up twice to get the class specific trophies, because every time you left, even if you were rank 5 on your end, server side it would reset you to rank 0, so you had to play two full ranks without leaving the server to unlock the class specific trophies. But none of them were tied to another trophy, where as here Jack of All trades is, so you would essentially need to get all 4 classes to 150,000 score on the same server, without leaving, to get Jack of All Trades, which no one is going to do.
DICE, you want to know where the problem lies and how to fix it? Maybe the thread above will help, it's marked as solved and the root of the issue is exactly the same.
Good news is that those trophies were fixed eventually, retroactively and you'd get the trophies as soon as you joined a match, so hopefully these do as well.