Commit 65bbf28d3c fixed issue HHH-10923 Closed and at the same time moved the javax.enterprise:cdi-api dependency from the provided scope into compile.

I'm not sure if that change was intentional or not but it can have an unfortunate knock on effect with hibernate-validator which since now requires a valid EL implementation. Since javax.enterprise:cdi-api pulls in a el-api, you now need to have the com.sun.el.ExpressionFactoryImpl class on your classpath. If you use a different EL provider that ships its own ExpressionFactory it may not get picked up (depending on the order of your classpath).