What should happen if a zone is already in an ongoing process and needs to be added to another process?

Example: "johani.org" is in the process "add-signer" (because a new signer was added to the signer group). However, that was a mistake, the signer should not have been added, so now it is removed from the signer group.

Normally, the zone would now enter the "remove-signer" process, but because it is already in the "add-signer" process instead we drop the "remove-signer" process and continue with "add-signer". Clearly the wrong thing to do.

On the other hand, if the zone was in, let's say, a "zsk-rollover" process for one of its signers and a new signer joined then it would make sense to let the zsk rollover complete before continuing with the add-signer process. Or?

It seems like we need a mechanism for "which process is able to replace what other process", or "which process is allowed to pause an ongoing process to sneak in before it". Hmm.