Hello responding here to see if anyone found a solution for this problem in QB Online.

For the past several months QB Online suddenly began sending duplicate invoice payment emails to my clients. The alerts cc our AP email address so I always get what the client gets. The symptoms seem to be random and are beginning to get frustrating as our clients feel like we're over-bugging them for money. 

Here are some scenarios from just this past week. 

1. I sent the same client A three new invoices. 1 of them showed up twice and 2 showed up only once. 

2. I manually sent client B and client C each a reminder invoice. Client B saw a duplicate invoice alert and Client C did not. 

3. QB sent automatic invoice reminders to Client D for four invoices. 3 invoices were sent twice. 1 was sent once. 

Things I've tried: 

• Checked invoice reminder settings. I previously had "send an automatic reminder" 3 days before and 3 days after invoice due date. I deleted the one 3 days after and instead of sending 3 invoice reminders at once it sends 1 or 2 which applies to the scenario above. If this is actually the problem, I haven't decided whether I want to make the tradeoff with automatic reminders.
• I've checked "recurring transactions". No clients are on this list. 
• I've checked the QB invoice email settings as my own email and AP email were both cc'd on invoices. I removed my own email to see if it made a difference which it shouldn't and it didn't. 
• Other people who are on the AP email address also see the same symptoms. 

4 out of 5 times QB support has essentially said "we don't know" or "there is no way to do that" so I'm hoping the community has new insight. Thanks in advance.