I just pushed a problem report to Quicken Support but thought I'd share in case someone has found an answer already.
I have 4 Fidelity accounts synced in QMAC, including a CMA account. Since 4/30/26, transactions are no longer downloading from the CMA account, though the account balance is correct and in sync. My 3 other Fidelity accounts are still working as expected. A couple weeks ago I did update QMAC from 8.x to 9.0.3, and because my CMA transactions are fairly sparse, the change could be related to the software update and not be related to the calendar date.
I've already tried disconnecting the CMA account and resetting / reauthorizing it. Given that the account balance is in sync it seems the account is correctly attached, but it doesn't recognize transaction activity.