some are just shy.
I only feed f/t* and one of my girls will take it like all the others, then drop it and ignore. I have to re-heat and then offer again and finally she will eat on that second coil. EVERY TIME. it's so annoying lol
You did mention this is an adult male, he may just not eat regularly. I have a few adult male BPs that will only eat every 3rd or 5th time offered, or go off food completely all winter for months.
Boiling water seems like such a pain to heat up the feeder in my opinion but if it's working and you don't mind, go for it.
I put my feeders in bags, then in a tub/tote which I fill with warm water. Dumping, replacing and flipping the feeders as needed until everything is thawed and warmed up. For those (mostly BP) that prefer the feeders very warm, I just do the last thaw soak in very warm water. Lots of people also use hair dryers to give a blast of heat to a thawed feeder. but again, if what you are doing works for you, no need to change
*unless some other issue requires live or trying to get new addition to switch