I get checked every single time I take my jpro through security

No problem when I went to hawaii last month from California or on the way back. They didn't even bother vs asking me to take out my notebook and tablet that was in same sleeve... -_-;
(my coffee bag had K-max, Small WaterPerc, Jar of Beans, Hario Switch, Filters, Scale).

I've flown with Feldgrind, Aergrind, Kinu M47 numerous times transcon, transatlantic and within Europe. For two years I (living on the East Coast) was in a relationship with a woman in Europe and would fly back and forth for a weekend AT LEAST once per month. To many different European cities.
I would usually take out the grinder right away, so TSA didn't have to dig through my luggage and leave a mess. The grinder got pulled out quite a lot but usually they just swipe it for explosives. The only bad experience I had was when some idiot officer dropped and broke an Aergrind, and I was late for my flight and didn't have time to file for reimbursement.

I also once flew transatlantic with a Kafatek MC3(!) in my backpack and that wasn't an issue either.

I finally completed my travel with picopresso - aeropress - 1zpresso Q2
On departure no mention of my backpack internals!
On return from Munich, there was a nice young person who checked if it was actually a coffee grinder and was very understanding!
Yes i had premium coffee all way long!

I don't have experience flying through European airports, but I have flown with mine in the U.S. Only once so far, and TSA pulled me aside and checked it out. Aside from the extra bag search, they didn't give me any problems.

All the metal parts definitely raises eyebrows when it goes through the x-ray. So, be prepared for a little extra screening, but I wouldn't expect further problems.