This has probably been brought up before but as a newish user I'm really surprised this is a thing. What is this, high school English class? I can't remember the last time I was forced to to this...literally in all my travels on the internet in the last maybe 10 years I haven't ran into another site that wants double-spaces after periods, quotes, commas, etc.

Plus...when you quote someone...guess what? All their sentences get scrunched because they don't have double-spaces after the periods. So either leave it and let it look goofy, or go back and edit it just to make it look right. Annoying af.

Also, the implementatoin seems spotty. Like sometimes seems to work where i don't need a double-space, and other times it seems to want one. I just don't know why.

I just feel it's a little bit funny that most of the site seems so slick then you have this stone-aged convention of dobule-spacing after periods. It really should be removed.

When you see the lack of a space after punctuation, just reload the page and it will fix itself.

It happens to me too. I don't know why it does this in the first place, but it's not that big of a problem.

It's a visual glitch only visible to you when initially posting something. You do not need to add any sort of double spaces whatsoever, just reload the page.

Besides that, this is a bug report, not a feature request, and you've also ignored the entirety of the bug report template.
Its also been reported at least 5 times now, and all threads have gotten the same answer: it's cloudflare mangling the returned body of the request, most likely for security purposes.