No I have not had this experience except for some short term issues over 20 years. That being said have you validated or Super validated you file recently. If not, before you try to do this make a backup copy of your data file first.
What banks are involved? Do you have credit card accounts as well? Have they recently changed the way they interact with the Quicken servers? I have found brokerage accounts however to be troublesome. I enter all of my brokerage transactions manually at the end of every month. My Fidelity account is an exception because it is an IRA account and that downloads fine.