Where on the roll did this fall, and how close to either end of the roll is this? I can't help but notice the example shot, when we see the negative, is near the end of the roll and in fact very curly in just the right directions to have possibly muddied things up, and even produced some of the odder effects at the bottom.
Also notice the darkening at the edges:
Are other frames like this?
Theory: (which may even reconcile a lot of the others floated, between solarizing and fixer and developer, and etc... ) Bad chemistry maybe, but possibly a glitch loading the reel means that some of that film was actually stuck to itself in spots: it got some developer which then essentially formed some suction. Mostly keeping the developer from refreshing itself even with agitation, also not taking on enough stop, also, insufficiently fixing.
So, this happens, maybe everything looks OK. You take the lid off the tank and rinse. The developer is mostly depleted, but still a bit active, having been stuck between the turns of the film reel... (also keeping most of the stop and fix out in the process: basically what you have is some good developer, but not enough of it, getting in there, but no more, and that's all.) And in certain places, according to the curl, it catches some light and solarizes-ish from light coming in, until it's finally washed away.., or the developer fully depletes itself while the film's hanging to dry....
Now, with re-fixing, you've stabilized it, but damage done.
The strange 'bokeh' would be there because that's where the active ingredients of the developer 'stuck' first.
Something like that, maybe?
I suppose, too, that it's possible, if this had happened with a faster film, things might look a lot worse.
Not sure.
Action plan, load reels more carefully.