My car started to make some noise from a tappet. Just random when warm. it comes and goes.

I had some other tappets, so i took out all the tappets. Checked which onces where still moving and placed all movings back in.

Car is still the same, so maybe i placed the bad tappet back in, but how can i recognize the bad one? It's only one that does it and i think its a shame to switch to all new onces

Anybody an idea?