The powered running boards deploy normally, or they deploy and retract, or one extends while the other doesn’t, or…any combination you can picture. Sometimes the dash shows the compass instead of the digital speedo and must be reset. Sometimes the power steering wheel adjustment is non-functional.

Let's check off the low hanging fruit stuff first:   How old is the battery?   Have you load tested the battery and made sure it is OK?    Did you check battery connections (positive and ground terminals) make sure there is a solid connection and not loose and/or dirty?

Would a fancy scan tool show any of these faults? 

Possible.  It just needs to be a scan tool capable of scanning all systems on a vehicle, so an "all system" scanner.   A basic OBDII scanner won't cut it.   An autoparts store should be able to scan for you (just make sure they are using one that scans all systems onboard), and I would jot down any fault codes that come up.   They can also load test the battery for you.

Scotty says that's tipical with Ford vehicles at 1:30

https://youtu.be/7ArDE0-_FRI?si=KbMmmv5_41uqHWEa

Thanks. I replaced both batteries at time of purchase (2020 @ 19kmi), and did annual Spring terminal cleaning.  I’ll load test them. 

Since posting my question, I’ve learned that a particular fuse box in these Superduty trucks is prone to water intrusion and potential resultant corrosion. That will be my focus in the morning.

Roger on the proper scanner. Much appreciated. 👍