Unclear from your title and description what is actually happening.
Did you accidentally assign a data drive to the parity slot?
When you removed a drive, parity was no longer valid, unless you wrote zeroes to the entire drive to be removed. Empty implies a formatted filesystem, which is part of parity, and probably deleted files, which are also part of parity.
Your title implies you put the wrong disk in the parity slot, but the body of your message sounds like everything is working correctly, you just need to unassign the parity drive, reassign it, and rebuild parity based on the remaining drives.