Dynamic filter null pointer exception

[edwardcawley]

This example from the documentation

curl https://{your_domain}.agilecrm.com/dev/api/filters/filter/dynamic-filter -H "Accept: application/json"
-H "Content-Type :application/x-www-form-urlencoded"
-d 'page_size=25&filterJson={"rules":[{"LHS":"updated_time","CONDITION":"ON","RHS":1572580800000}],"or_rules":[],"contact_type":"OPPORTUNITY"}'
-v -u [email protected]:123fghfhf******* -X POST

(but with correct credentials etc.) fails,

{"exception message":"java.lang.NullPointerException","status":"500"}

I have tried this on two different agile accounts. The issue seems to be OPPORTUNITY, I can get data with the dynamic filter and PERSON in contact_type.