Voltage drop to water heater
FINAL UPDATE: I replaced the breaker, and took the opportunity to remove the wires going to the Load Control box, which from all apearances is no longer being used. I was relieved to find that the splices underneath were done with crimped splice caps, and then covered with the electrical tape.
Everything checks out good with votage at the heater and back in the panel box now.
I appreciate everyone who commented and served as a sounding board so I could confirm what I was orginally suspecting!