mail.app jumping cursor
Only the mail.app is affected - new Macbook Pro 2015 High Sierra 10.13.3
Appears to affect only one of two users.
When writing a new email, focus will jump from body text to another paragraph, subject, or receipients seemingly at random. The problem can replicated. Main user was migrated from Time Machine. A new "admin" user does not display the problem.
PRAM and SMC have not been reset. plists have not be deleted.
MacBook Pro TouchBar and Touch ID, macOS High Sierra (10.13.3)