Really hard to say what’s going on. Which maybe means there’s more than one thing going on here. I agree that issues with the left side of the print could be cooling related. But this looks almost like you’re under extruding. But the top of the extrusion should still be flat, the layer height is less than the extrusion diameter. And especially with these loops at the edges, the filament top is clearly nice and round. Like the nozzle is too high here. Which might also explain why the filament isn’t sticking to the underlying layer. Sticking requires the new layer to get squished in to the previous layer. If the printhead is too high that won’t happen (which is why supports with the same filament as the print are printed with a gap that is 1/2 of the nozzle diameter, so the extrusion will just rest on the previous layer). If the nozzle is too high, under extrusion will tend to cause the filament to get balled up. It doesn’t stay where it’s put, it’s under tension because the filament is flowing a little slower than the nozzle is moving, so it gets dragged along behind the nozzle. Every time the nozzle changes direction that string gets wrapped around it. Except, why would it only be higher for this top layer?
Given that the other filament works much better, the primary issue here has to be filament flow or PA. If it was mechanical it wouldn’t care which filament you were printing with. Unless the filament is only marginally tuned and a mechanical issue in this corner brings it out. You need to run the calibrations and also do a temperature tower for the “uglier” filament and see if those tweaks at least make it equivalent to the “prettier” filament.
As for why that corner, assuming the chamber and aux fan isn’t running, I dunno. Hard for me to imagine it’s cooling related. Why would that corner be much hotter or cooler than the opposite corner, for example? Front of the build plate, with air gaps around the door, yes. But not the back. And if it was the build plate, I’d expect it to mess with the first layer not the last.
Things to try:
If you rotate the model 90º on the build plate, does the issue stay in that corner or follow the model rotation? If so, there’s something funny with the model (I doubt this is it).
If you scale the model down to 1/4 size and print it so it’s still in the same left/rear position, is the issue still there? (this will change the outcome if it’s cooling related)
Tram the build plate. And then run a straight edge across the back edge and left edge and see if that left rear corner is low. The auto-level doesn’t measure everywhere, if the build plate height changes unevenly between the sample points, the printer doesn’t see it. (I’m not sure how I can see this being it)
Dry the “uglier” filament a lot longer and see if that makes a difference.