There are many open bugs on meta related to incorrect email reply parsing and I have been looking into them since past few days.
Almost everytime the fix is to correct/modify something in GitHub’s email_reply_parser library.
The GitHub’s email_reply_parser library is now abandoned. The last commit was over a year ago, and there are many open issues / pull requests.
I propose that we include the email_reply_parser in core Discourse email library so that we can customize it as per our requirements, without depending on GitHub’s library.
I have laid the groundwork for this, and in process fixed these bugs:
Here is the PR for the same:
Looking forward to hear @team’s feedback/suggestions.