Nowadays if this happens, I just message the team and say something to the effect of “if you rush ahead of the venom, that’s fine by me, but I’m not going to be able to help.” They soon change their tune.
I think part of it is that Lahni/Blademaster is probably disproportionately affected by venom/lack of venom compared to the other Hivebusters characters. I mean, with ultimate recharge so connected to damage delivered, it’s not always a big issue for Keegan/Tactician (although the difference that Venom Boost makes is a very big one!) just because explosive weapons are by nature high-damage. With Lahni, there’s a different kind of a chain for her which relies on venom - venom = extra defence. Venom = bleed damage; and bleeding enemies leads to extra healing.