Luke Le on 18 Sep, 2019 05:39 PM
we are very sorry for your bad experience.
Unfortunately the behavior your are observing is caused by a bug in macOS Mail on Mojave. We have filed the bug with Apple but it is unclear how long it will take them to resolve the issue.
Our latest GPG Suite however includes a workaround if you install it directly from the website: https://gpgtools.org