Deleting emails where I am BCC'd from the inbox
I have Always BCC myself turned on in my iPhone mail settings. Recently, whenever I delete the BCC'd copy from my inbox, the email also gets deleted from my Sent items folder. If I delete the copy from my Sent folder, it does not delete the copy that's in the Inbox. I tried this with both my Exchange account and my Gmail account and am getting the same results.
I initially thought this might be related to me having threading turned on, but I have turned this off and am still encountering the same issue.
Is there any way to fix this so that I can delete the BCC'd copy from my inbox without deleting from my Sent items folder?
iPhone 12