I think I might have found a oddity in hibernate-validator 6.0.15.Final. It used to work with the version 5.4.2.Final.
Here is a test example:
The BigDecimal stored in a Number field will not trigger a constraint exception even though it is bigger than 1. And a bigdecimal such as 2.xxx would.
It feels like the validator does not (anymore) take into account the numbers after the comma in BigDecimals objects stored in a Number.
java version "1.8.0_201"