other players have described this phenomenon something like this:
if you start sanctification on a hero check what the first few stats are and the following ones will be like those until it switches. for example if you are getting 3 yellow attack stats you are most likely to get more yellows like it until it switched to purples and then blues. if you dont like them, reset and try again.
that worked until recently where the GM's started messing around with the hero cards (blues changed, tavern changed, new heroes added, blue changed again, tavern event changed, purple stats are now yellow, etc...) and since then we dont get the above structuring but some random adds that let it switch from getting yellow to getting white and then a purple if you lucky.