It could easily be the POT. Had one of those go bad on us back in 2013 - we had a 2-jointed arm connected to a winch, all running through a feedback system so everything worked smoothly together. Programming it was a huge pain, but a cool little bot. Anyways, fall of 2013 we were in Manchester for the Alpha Test weekend for the RoboRio and things weren’t working right. Turned out the pot that had made it through two regionals and two off-season events went bad. Replaced it, re-calibrated everything, and no more problems… with the robot. The broken pot ended up in my pocket, and then from there into my suitcase (probably when I emptied my pockets while waiting in line at the airport to go through security). The TSA saw it on the scanner and I got to spend a good long while talking with them because it was “suspicious”. Ugh.
But I digress. Even a slight misalignment on the pot will eventually wear something out and break it internally. You won’t be able to see it, but you can measure the difference with a multimeter while manually moving the mechanism - unplug the pot and measure the resistance across the signal and ground pins. You should see it change from near 0 ohms on one extreme to near the ohm rating of the pot on the other, assuming you’re using most of the travel of the pot. While the elevator probably has enough force it in that a broken pot wouldn’t impact its movement, if it is busted and you pull it off, you’ll probably be able to tell just by turning it by hand - ours was really stiff and felt like something was grinding.
After that, I would look at the power and signal pathways. Based on the LED’s on the talon, it sounds like it’s getting signal and power just fine. Check the pot pathway assuming it’s plugged right into the talon. Check the power pathway from the talon to the motor as well. If you have a connector (power pole or something else) in that pathway, there’s a chance that the heat of the day, combined with constant running, caused some problems there - I’ve seen a wire for the RSL burn up during a parade before, so anything can happen! If the casing of any connectors deformed from heat buildup, it could have essentially disconnected the motor.
If you have a o-scope, you could check out the output of the talon directly. It’s actually a pretty cool learning exercise for the kids to see how the output waveform changes as the speed you’re commanding it changes, and then how hooking a motor up to it averages out the voltages so you don’t even see the waveform anymore.