Validation Group is not working properly

Try removing the validationGroup in the a!dateField() and keep only on button or  buttonWidget- . My CE site is down so could not try validate but this change could work 

Refer this

docs.appian.com/.../recipe-use-validation-group-for-buttons-with-multiple-validation-rules.html

Personally I've always found ValidationGroup functionality to be unintuitive and cumbersome to implement, use, and/or test, with results that are inconsistent with expectations or designed intentions.  Thus I typically use other methods to enforce validations under certain circumstances, beginning with making sure my forms are scope-limited where possible, and also, abstracting certain form functionality using local variables (such as variables keeping track of validation status of certain elements if needed).  Without knowing a bit more detail about your particular requirement or intended design, it's hard to offer much more of a concrete suggestion than this.