I experienced a similar issue related to system.owner in a recent versions of Mendix, and I believe there may be a bug related to it in some way.
As a workaround, you can turn off the “Store owner” checkbox for the Request entity in your domain model. If that causes errors in your model (i.e., your app is using the owner somewhere) you can add a new association from Request to User, and set that association whenever you create a new Request.
This might help, I found another question with a similar issue: https://forum.mendix.com/link/questions/92530
Additionally, if you search the forum for some of the strings in the error message, such as “java.lang.IllegalArgumentException”, you find a lot of results in this forum and on Google. Since I am not working through that module as you are, this is about as helpful as I can be. Good luck!