It's good to have you here, @ngorzkiCEA.

I can see that you posted the same question my colleague answered. You can look for it by clicking this link: https://quickbooks.intuit.com/learn-support/en-us/payments/re-attachments-are-missing/01/1364476#M5...

If you have additional questions about managing your invoice, please reply. I'll be willing to help. Good day.

 This has nothing to do with payments and file size is under requirement of 25MB. 
The invoice is there, the additional non invoices are not. If I email them right away, all attachments stay so this not a “rebuild data” situation. 

Thank you for getting back to us, @ngorzkiCEA.

Let me share some information to help you resolve the issue of the missing attachments of your invoices in QuickBooks Online.

Before we proceed, I would like to clarify that the article about the payments provided by my colleague is for future reference once the issue is resolved.

If your QuickBooks Desktop is updated to the latest release, I recommend contacting our Customer Care team.

Here's how:

1. Open QuickBooks.
2. Go to Help, then select QuickBooks Desktop Help/Contact Us.
3. Select Contact Us.
4. Give a brief description of your issue, then select Continue.
5. Sign in to your Intuit account and select Continue and then Continue with my account.

• If you don't already have an account, make sure to Create a new account.

1. We'll email you a single use code. Enter your code and select Continue.

• If you have more than one account, select the account you want to use and then Continue.

1. Select to chat with us or Have us call you.

I would also like to add this article for future reference to learn more about common questions with Documents: QuickBooks Document Center: FAQs and common issues.

Don't hesitate to click the Reply button below if you have questions about managing invoices in QuickBooks Online. I'm always here to help. Have a great day.