A font that is required for this encode has changed. Please restart the encode.

[Ldoggs]

Have recieved the following error in AME when exporting from Pr: 

A font that is required for this encode has changed. Please restart the encode.

Can you help explain what may be causing this issue and/or what this error means? 

I use Monotype and system fonts and they were online. I had a dynamic link project with AE  which contained some text, which was also online. 

Restarted Premiere same error, trashed cache then restarted Premiere fixed the issue. This has been happening at least once a month for the past 6 months or so so is making me wonder what I could do to prevent this moving forward. Currently running 23.0.