Divide by Zero error when using Exflow with D365 FO

We are using Procurement categories rather than Items, but are seeing an error ‘attempted to divide by zero’ when using Exflow invoice matching when we try to retrieve the Receipt to enable invoice matching. Seems to be the ‘Price Unit’ field which defaults to zero (which we cannot change the default). Anyone seen this and have any ideas how/where to manage this in the D365 config anywhere?