Incorrect HTML email rendering

[senchden]

• This is not a feature request (existing functionality does not work, not missing functionality).
  I will request features on forum or via support.
• I've searched and did not find a similar issue.
  There is a similar issue some html emails cause rendering issues #6581 , but it was closed by adding a source viewer. As far as I understand it did not actually fix the issue.

Bug in web app, desktop and Android app

Describe the bug
Rendering of some HTML emails is broken - no readable text is visible.
I am enclosing a text file with the pseudonymized message source.

To Reproduce
Steps to reproduce the behavior:

1. Attempt to render the html code in the enclosed file in any app - web, android or desktop.
   tuta-incorrect-display.txt

Expected behavior
The message is rendered correctly.

Screenshots
Example of incorrectly rendered email:

Example of expected rendering:

Desktop (please complete the following information):

• OS: Windows 11
• Browser firefox 125

Desktop app version v227.240502.0

[wrdhub]

Thanks for your report. Like I mentioned in the other one we decided to add a source viewer to help us figure out what is going on here, we should have properly updated the other issue to reflect that. We are still looking into this!

[wrdhub]

Test Notes

• Check various plain text and html emails, make sure they display