I have been told that the issue was not present in your actual e-mail message for e-mail readers. I read via the web interface, so I've asked the group owner whether e-mail address masking is still turned on when viewing the archive. If it is, that explains the situation, if it isn't, then I need to file a bug report with Groups.io support.
By the way, in the latter half of your original message and all of this one, your text is coming through as white on black background in the web interface, which I've never seen happen before. Are you using something that does this?
Brian - Windows 10 Pro, 64-Bit, Version 1903, Build 18362
Many of the insights of the saint stem from his experience as a sinner.
~ Eric Hoffer