This just seems really weird to me. Why would it stop just because you are fighting? This makes it so that unless you are dealing health damage, an skirmishing or harassing of the monster outside the dome is actively detrimental to your team, since the monster is able to move, feed, and make progress toward evolving, all while the match timer is paused and it can simply regen it later.
I can understand why it needs to stop in the dome, otherwise the hunters would be incentivised to not engage in the dome or even solo dome and then just take the down on that one hunter in exchange for about half the monster’s time. But stopping it based on damage to the monster is just wrong.