Upper bound on probability of hero offer?

[Experix]

Hi, I am not sure whether it is a bug, but while playing with hero offers, I got some suspicion that having a lot of money, I get offer every turn.
Tried to test it more. 2 heroes (I didn't accept any more offers from that point), 3000 and far more gold. 13 turns in row I got a hero offer. If the upper bound was 75%, that would mean the probability of this happening is approximately 2.4%...