Thank you for choosing the Community to assist you with your concern today, @tanghorty.
Allow me to help share insight about the Systems Administrator access in QuickBooks Online.
The System Administration user shows changes made automatically by QuickBooks Online. It's possible these transactions are recurring, added data through bank rules, automatically applied for credits, and added from a third-party app.
If you're unsure, I recommend visiting the Audit log section and view the details. This way, you'll be able to identify and track the transaction.
Here's how:
Click the Gear icon in the upper-right corner.
Select Audit log.
Filter the information if necessary.
Search for the event in question.
Press View below the History column.
I've attached some articles below for additional reference about using the audit log feature, as well as creating recurring transactions: