In 2.2.29, as part of #4853 a new config property was introduced, groupsValidationStrategy. It looks like #4853 introduced a change in behaviour of how validation constrains are being resolved because the description of that PR states:

Previous behavior (resolving validation constraints regardless of groups) can be accomplished by passing new configuration property groupsValidationStrategy=always

I attempted to apply this by setting the new property on ResolveTask in the Gradle plugin, called groupsValidationStrategy. Sadly, due to a bug on line 557 the value of that property is not passed on to SwaggerLoader unless defaultResponseCode is also set. I assume this is a copy paste error and the line should read

            if (groupsValidationStrategy.isPresent() && StringUtils.isNotBlank(groupsValidationStrategy.get())) {

rather than

            if (defaultResponseCode.isPresent() && StringUtils.isNotBlank(groupsValidationStrategy.get())) {