In the lastest version of Vray (5 2.3) in 3ds max 22 a crash occurs every time a light with a VraySoftbox texture is applied to the texture map slot gets hidden/unhidden in the scene explorer menu. The multiplier can be changed as well as the ‘On’ tick box can be used no problem.
This could be tied to the other bug with hiding lights while IPR is going.
Could you try this stable nightly build and see if it fixes it for you?