Hi Swagger
Greetings from Syncfusion support.
The drilledMember option always works in vice-versa with respect to the property expandAll in pivot table. For example, if expandAll is set to true, then the member(s) added in items collection alone will be in collapsed state. If you want to expand all items in the fields then you can empty the drillmember collection before expand all or collapse all button click. We have prepared a sample for you please find it below.
Please let us know if you have any other queries, we are happy to assist you.
Regards,
Mouli