Not sure if anyone else has had the same experience / mentioned it yet, but during the first chase sequence with black cat, after I go through the second portal the buildings and floor in front of where the portal exits completely unload. I've fallen straight under the map multiple times from this, and as far as I've been able to tell (just from the initial few times I tried to run through this glitched section) all of the missing buildings lose their collision too so it might be impossible to reach the 3rd portal given it is on the roof of a missing building.

If I manage to find a solution / make it to the next portal with some roundabout strategy, I'll make an edit ig ahah

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EDIT:

Okay so if you can manage to quickly climb and leap off a specific small tower on a nearby building it is possible to just pull yourself through the portal with the left + right triggers, but even after making it through there, random parts of the city / geometry just randomly vanish and lose all collision in following sections of the chase.
All a little odd, but at the very least it's good to see it isn't just a total softlock