What is your VIP level? I did not gamble much on Stake lately, maybe less than $5k wagered amount in the past 30 days and my VIP rank is Platinum 1. Did you get it in reload or one time bonus?
I do not think that it is strictly about the VIP level (I am sure that plays a part but not 100% all of it) because I played with less and ended up with more, so I am guessing there are other things in play. Basically, stake became a bit of a place where things are a bit more "random" if I have to be honest, I have a "friend" (just a guy I chat on telegram few times a week) and he wagered a lot less than me but he wagered A LOT more than me before, so he got more this time around, so it is not strictly about just this month neither, so I am sure VIP level does play a role here as well.
It is basically a bit weird calculation that we don't really know all too well, I have no idea how it is calculated, or maybe it is really purely random who knows? I also love it that after another crypto place, Watford went with stake as well, they had a crypto casino sponsor for the past 2 years and now on to the third year.