No issues here, with stacking Bryston components on different shelves. BDP-1 on top of BCD-1. BHA-1 on top of BDA-1.

I am experimenting with vibration control and it is certainly not at all cut and dry for me personally.
I have a Salamander Synergy three bay unit and I just tried Stillpoint SS under my ARC REF 5Se and at first I thought it was an improvement then it became apparent that the mids and highs were less layered and too bright. I could easily pick up the change in the sound by just inverting the Stillpoints as well, likely the sensitivity of the tubes to changes in levels of vibration.
I then tried them under my Kuzma table base first then added the second set to the ARC Ref phono pre and each was a welcome improvement across the board. Better image and better low level detail.
I have stacked Byrston BDA-2, BDP-2 on shelf with SSD sitting on top of the player. I also have 7Bcubed on separate stands and will order Stillpoint mini SS and try on each of the Bryston components and report back.
It is possible that the Quadraspire rack does a good job of reducing vibration travelling between shelves and provides an overall lower level to start with versus the Salamander rack.