[vermarish]

I suspect you are right when it comes to analog circuits, but they are definitely LTI in a typical digital implementation. I checked this by adding reverb+delay and delay+reverb to two copies of a track in REAPER. I inverted the phase of one, played them together, and they cancelled out.

[reom_tobit]

I would be very surprised at that! I have no time currently but I can put together a example for you to illustrate what I mean if you’d like.

[vermarish]

No stress, but yes, I am curious.