"Invalid Input" when attempting to save changes to a change workflow

"Invalid Input" when attempting to save changes to a change workflow

Hello, we have successfully created change workflows, and associated them with templates in our change module. After doing some testing, I went to make some minor changes to one of my 3 workflows. When I attempt to save, I get the "Invalid Input" error (attached); even if the change is very minor (for instance, changing verbiage to the description or adding a status to one of the stages that was not included before.

I've since tried to make some minor change to each of our 3  workflows, and for every workflow,  regardless of what kind of changes are made, I am getting the "Invalid Input" error.

For reference, my technician account has both SDAdmin and SDChangeManager permissions.

In addition, I am able to create brand new workflows and make changes to them.  We are using 11.3 Build 11302

What could be the issue here?