The documentation on the filter-ref attribute 'priority' in the undertow subsystem [1] suggests a filter with a higher number (e.g. 2) is executed before a filter with a lower number (e.g. 1). It appears to be the opposite.

"Defines filter order. It should be set to 1 or more. A higher number instructs the server to be included earlier in the handler chain than others under the same context."

[1] https://access.redhat.com/documentation/en-us/red_hat_jboss_enterprise_application_platform/7.1/html-single/configuration_guide/#location_filter_ref