Are both snakes in the same cage together? If so, I personally would separate them and have them live in their own cages. That fact alone could contribute to feeding troubles, or it may not, but something to consider. Sometimes snakes can get stressed with cagemates.
My black pine was very inconsistent in her first year/year and a half of eating, until I found out what she wanted. She wanted me to wiggle the food in front of her. So, when I started doing that, she eats the mice each and every time, no problem. Give that a try.
Also, I have found out with some of my snakes in my collection, if you thaw out mice, and they tend to cool off some and lose their warmness from the hot water they were thawed in by the time they are fed to the snakes, I had a few snakes recently not eat them at first. Before this happened, there was no problem ever with them. I then just placed the same mice back in the hot water for a few seconds, warming them up, and then the snakes took them instantly. There were several instances where these snakes did this same exact thing, so that led me to believe that they were preferring the food to be as warm as it could be. That may be something to think about in your situation as well.
For those snakes now, I feed them first before any of my others.
Take care and good luck.
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Genesis 1:1