Pretty sure this is a stretching issue, IOW you need to stretch. Needing to stretch increases with age. That's simple, no problem. Just need a routine to do every morning. I had the same thing happen many years ago, had to pedal the rest of the way one-legged. Stretching fixed me right up, never happened again. See: IT Band pain (during ride)
I did stretch like this 3X day for a few days.