Thought sabotaging enemy equipment to explode isn’t.
Had this been a bunch of Russian or Wagner Group radio equipment exploding because they had been rigged by Ukraine, it wouldn’t be a war crime - combatants don’t stop being valid targets even if they are on leave and are at fault of endangering the civil population, possibly themselves causing a war crime by effectively using civilians as human shields in the process.
When you are a paramilitary organization, the line between what is military equipment and what isn’t gets quite blurry. Especially when they weren’t really “boobytrapped”, they were turned into remote explosives and did nothing until explicitly triggered.