I don’t believe I’ve ever seen any message deletion sync over to another device. I can delete a message on my iPhone but I’ve also got to delete it on my iPad. Yes, both devices are signed into the same Apple iCloud account. This is what is suppose to happen but I’ve never seen it:
“If you have enabled Messages in iCloud and are signed-in to iCloud with the same AppleID on both iPhone and iPad, your messages will be fully synchronised between devices. Deletion of a message on one device will delete the message on all devices.”
Anyone else?