If true, this is a war crime by Ukraine.
On the other hand, I find any Russia reports extremely suspicious. While this is completely not out of the question, I would be skeptical that Ukraine would be engaging in sabotage of this sort which is both extremely damaging to PR and of only marginal use.
If it was "Ukraine had engaged in a policy of committing war crimes to regain Crimea" or "Individual Ukrainian troops or units were found committing war crimes", it'd be more believable, but "Ukraine is committing war crimes just to harass Russian troops" seems like something that would need additional verification before I'd lend it any credence.