Thanks for your feedback.
If you still experience the problem in version 3.2.4 please contact us directly through the ‘Contact Support’ button here – http://support.termius.com/
Would be great if you can provide us with the auth logs as well.
This bug is still occurring every single day... Terminus 4.1.2, OS X High Sierra 10.13.6
"Work-around" is to edit the host, remove key, re-attach key... probably not worth subscribing until this bug is fixed.