Gross weight is not a factor and actually it is easier to get into VRS at a low GW.
It is a factor simply because it is easier to get into VRS at lower weights - low weight equals less downwash speed (less collective pitch) equals lower RoD required to catch up with the downwash.
Pilots can be lulled into a false sense of security flying a lightly loaded helicopter - they have bags of spare power and VRS is often the last thing on their mind.
Just the sort of time you might be tempted to continue with a steep approach that you would otherwise have gone around from - you've got loads of power so where's the problem - if you had been heavy, you would be more careful about your approach.