macOS High Sierra version 10.13.1 resets mail preferences

Since upgrading to macOS High Sierra v10.13.1 the Apple mail preferences are reset to factory defaults each time I restart mail.

Frustrating to have to change mail preferences every time I start mail.

For example:

I choose show newest message on top, but mail resets that to show new messages on bottom;

I choose to automatically bcc myself when replying, but mail resets that to not copy me;

I choose not to increase quote level when replying, but mail resets that to increase quote level;

I choose not to include a default signature, but mail resets that to include a signature...