Good morning, @hbnine.
Thanks for joining the Community with your question about the banking feature. I can provide you with some details on why your bank may have missing entries.
The reason some transactions may be missing is because of your connection between QuickBooks to your bank. Sometimes this may lose connection to where your transactions don't load completely or you get an error. However, you can manually upload the missing transactions so they'll be listed in QuickBooks.
Here's a guide that has detailed instructions on how to add these manually in the system: Manually upload transactions into QuickBooks Online.
I hope this answers your question and helps fix the issue. I'm only a post away if you need me. Take care!