Burden transactions were created without any Burden Setups. How can we see how they were created?

Oracle Projects

12.2.10

Hi all-

In auditing some recent transactions in Projects, I found two expenditures with an ET Class of "Burden Transaction." There are no Burden setups in any of our OUs - we've simply never used them. I confirmed that there are no setups for Burden Cost Codes, Structures or Schedules. I also asked the user whose ID is attached to the transactions how he created them and he had no idea. I looked at concurrent requests and no Burdening programs have been run.

Any idea how these might have been created or how I might investigate this?

Thanks!