Comment by arkadiyt

This is fixed in iOS 12.3 [1] and macOS 10.14.5 [2], both released on May 13th. As Natalie noted on the ticket, turning off iMessage will also prevent the bug.

[1]: https://support.apple.com/en-us/HT210118

[2]: https://support.apple.com/en-us/HT210119