Thank you for this post. Unfortunately I can't help because I currently have the same problem.
I have already tried it with a compact <500kb-version of the profilepic which also didn't work because of a picture-size-limit I've heard about although it seemingly only applies to video-thumbnails and not profilepics and -covers.
And with my profilecover-image it's the same problem although I haven't tested it with a <500kb-version because I think it wouldn't look so good.
I also think the problem has nothing to do with the used browser because I already tried it with Brave, Chrome and Firefox.
RE: Dtube / Steemit Profile Pic link problem