RewriteFilterBehavior::rewriteCondition() expects Filter\Condition but allows Filter\Rule to be returned. This can also return Chain, such as in FlattenedObjectVars. This breaks any behavior that follows a behavior that returns something other than Filter\Condition, as behaviors are processed sequentially, using the previous behavior's result for the current one.
RewriteFilterBehavior::rewriteCondition()expectsFilter\Conditionbut allowsFilter\Ruleto be returned. This can also returnChain, such as in FlattenedObjectVars. This breaks any behavior that follows a behavior that returns something other thanFilter\Condition, as behaviors are processed sequentially, using the previous behavior's result for the current one.