Hello,
I have enabled a filter widget and SQL Expression Builder clause set. To get multiple selections I've used "is any of" and 'Values filtered by all other expressions".

But when implemented I get strange behaviors. The first clause allows selecting multiples but others act differently. When I select the second clause the choices disappear after the first pick. However if I can click really quickly, I can sometimes get multiples. My other dashboards using other data work as designed. See below.