I know I'm a bit late to the party here @ToddMartin, but this is something I've seen with outwardly published CRM systems that utilize SSL (or any secured protocol deployment) - specifically 2017 R1 and later. Unsure of when the bug was actually fixed as you indicated it was in later versions.
There's a couple elements at work... because of the extra ""/"" following the server name, it breaks the URL that shows the Notification icon. The URL to the icon is stripped of everything and usually only on the dashboard, so it will display a broken image. If you're looking at the browser console (IE or Chrome) and you hover over where the icon should be, you'll notice pairs of errors that'll accumulate - one for not locating the image for the Notification button in a hovered state and a normal state (see ""image.png"").
Since it's generally cosmetic and limited to the dashboard, I threw together a fix that I employ via a custom JavaScript file. There's essentially two fixes for this...
1) If you simply remove the extra ""/"" and hit the [Enter] key, it resolves the broken image and onscreen errors. However, most users won't bother to do that.... so... second fix entails...
2) The resolution to fix it is essentially rebuild the image's URL - see ""fixNotificationURL.png"" attached.
A bit lengthy, but hopefully there's some insight with my limited exposure to the issue.