After doing more trouble-shooting, I went back to a save file from before Lae'zel's untimely demise and noticed that she was still having trouble jumping in combat, this time when using my M&K hotkey (bound to the down-arrow since I mouse left-handed). That was when I noticed the particular jump action the hotkey was defaulting to was orange instead of blue.

Here's what I see when inspecting the orange Jump button vs the blue one...
https://www.dropbox.com/scl/fi/5rbx...rlkey=31xb902rmzvnt3hlwww0wzkyq&dl=0

Even though both jumps are listed as Class Actions, the orange one is is actually coming from a pair of gloves called "Fleetfingers"...
https://www.dropbox.com/scl/fi/yjsq...rlkey=g4sanyjnw76v28w36rki5hxb7&dl=0

I'll have to double-check the behavior with a controller later, but it looks like the issue here is that the Jump hotkey isn't "smart" enough to select the appropriate jump action for the currently available actions. If that can't be improved upon, then the best course of action would be to ensure the Jump hotkey remains associated with the default action, and/or to reengineer how these gloves actually work.