I called PPS a couple weeks ago on 2 of my returns that were stuck like that "in processing", all they could tell me is that they were in review and if the clients hadnt seen anything from IRS in the next 30 days, to call back....one finally got their refund on Tuesday...havent heard from the other client yet.

Yuo can try calling PPS, if youre the preparer and 3rd party designee they will look up the status of up to 5 clients per phone call.

https://www.irs.gov/tax-professionals/practitioner-priority-service-r