No, I absolutely would not be surprised. I'm retired after about 35 years in the HVACR industry, not to mention Florida Junior College where I originally trained for it. Hello, and happy to see you that way here. Never caught that on previous threads.
Don't know about your experience, but I retired at the top of my field doing full redesigns and modifications to everything the manufacturers were putting out when it suited me, to make them more than they were ever incorrectly designed to be. Working on chiller and boiler systems for hospitals, schools, etc. got to be actually boring for me in the end, modern electronics started doing my job for me. To a certain degree. Always preferred taking the stuff that should have been (or was by others) condemned long ago back to life for many more years.
I used more rod couplings hanging Solaronics gas-fired infrared heaters in factories and warehouses than anywhere else, your experience with those couplings in shops means we inhaled a lot of the same dust.