Selected shield type changes between first and second deployment

I've not seen this discussed elsewhere, but it is a longstanding issue with me, ever since Prime was rolled out (I use Android, and have done so on several different Motorola phones since Prime was released).
It is this: sometimes (certainly not all the time) if I am trying to deploy two common shields, after deploying the first common shield, instead of the selector sticking with a second common shield, instead it will move to select a very rare shield, which will then get installed instead, unless for some reason I have been paying particular attention and catch it first, that is.
(I typically have no rare shields available to be selected, since I put them in breeding capsules; I assume if I had a rare shield out, it would have been selected instead of a very rare shield).
This happens even though there are more common shields available to be deployed/selected.
This is very irritating to say the least!
Comments
It can happen not only with common-> vr but vice versa and with all mods in carousel. IDK why this happens.