Morris They must've changed something
The conditions are explained in this document: https://assets-global.website-files.com/63b43f001c7774d38d5f3a2d/63c65816108825c4b19a20fe_20230113_terms_WoF_EN.pdf They wouldn't be able to change them nilly-willy without documenting it, as this is a regulated luck-based game.
However, instead of there being a certain percentage chance to win a prize, there's an overall fixed number of monthly prizes per month that are given out. This means that if more people participate, then your individual chance to win something will decrease. This is probably what we're seeing, as bunq seems to gain more users lately.
In fact, they have actually increased the overall number of prizes if you compare the previous terms (for the period of Oct 11, 2022 to Dec 15, 2022) with the new one (valid until Mar 23, 2023). On that note: I won 1 Euro yesterday :)