[2022] Deep core mining always failing

I need help, i've been deep-core mining more or less since i started the game 8 months ago, i took a break for about a month recently and, when i came back, i went back to deep core mining so i could get used to game controls and stuff like that, but whenever i plant seismic charges, it almost always exceedes. And what i mean by that isn't that when the charge itself enters the asteroid it says yield exceeded, it's always when it detonates, even when it's under the idela yield, it somehow jumps to max yield or extremley near it. Is it a bug or have i just become bad at mining?