Steps to reproduce:
setup jira 7.2.1 with jsd 3.2.1 and jeti 7.0.25
create incoming jeti mail handler
setup Service desk mail handler to create or comment
set flag to comments always visible
comment as customer via mail
edit this comment as agent, chose "share with customer"
comment is visible for customer
comment is marked as internal and no chance to change
Thank you for your feedback, we are investigating this problem.
We have the same problem except it happens for us even if we don't edit the comment.