From time to time we may change various bear properties or statistics. E.g., a bear that previously provided 15 extra seconds in timed mode might now provide only 10 extra seconds, or a bear that previously provided a Final Score Bonus of 300% at Level 2 might now provide a 2500% bonus instead. This is a normal part of a game's lifecycle--certain things are nerfed (made weaker), buffed (made stronger), or otherwise changed to bring things in line with how the designers intend the game to work (and this intent may change over time). Sometimes the changes are minor, and sometimes they are drastic.
These changes should never alter your bear's level--a bear that was for example Level 2 prior to any changes should still be Level 2 after the changes. And if your bear's level has remained the same, then after the changes your bear should be exactly as powerful as it is now intended to be. This is especially the case if many bears were changed in a similar way (e.g., if all Common bears had their Final Score Bonus increased by 200%).
Feel free to email firstname.lastname@example.org if the change seems like a mistake. (E.g., "All the other Rare bears in this chapter now have Final Score Bonuses of roughly 3000% at Level 1, but this Rare bear at Level 1 now has a Final Score Bonus of only 300%. Did you forget a zero?")