Theres a property you can set to show only one error per field
maxErrorsPerField: 1
So you can do something like this
$('#formVa').validationEngine(
'attach', {
promptPosition : 'topRight:-90,15',
scroll: false,
autoHidePrompt: true,
autoHideDelay: 2500,
fadeDuration: 0.3,
focusFirstField : false,
maxErrorsPerField: 1
}
);