Created attachment 145077 [details]
Example of original and replied e-mail

SUMMARY
***
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***


STEPS TO REPRODUCE
1. Open an HTML e-mail with template cursor on top and ending with %TEXT
2. Write the e-mail content without changing anything on original HTML
3. Check that the composer content is visually OK and then send the e-mail
4. Check the received e-mail that is had its HTML modified

OBSERVED RESULT
The sent e-mail visual content differs from what was been showed on composer, even the original HTML that got some bordered tables on olders signatures and other parts of the content.

If sent e-mail is sent as text instead of HTML, original e-mail is also changed, for example, all images changes to somthing like [cid:image20c6be.PNG@dff82cd8.4ebe199b], not as a code, but as visual text


EXPECTED RESULT
At least the unmodified original HTML content from previous e-mail should not be changed, especially if it were left untouched

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: 5.20.5
(available in About System)
KDE Plasma Version: 
KDE Frameworks Version: 5.78.0
Qt Version: 5.15.2

ADDITIONAL INFORMATION