NoDataProcessedException on Invoice and Payment Put

[CartoJun3]

I noticed today when attempting to upload a set of invoices and payments pyxero gives the following:
Traceback (most recent call last):
File "", line 1, in
File "/usr/local/lib/python3.6/dist-packages/xero/basemanager.py", line 202, in wrapper
raise XeroBadRequest(response)
xero.exceptions.XeroBadRequest: NoDataProcessedException: No data has been processed for this endpoint. This endpoint is expecting Invoice data to be specifed in the request body.

There is no issue using xero.invoices.get or xero.payments.get, but the error is raised on all attempt to use xero.invoices.put and xero.payments.put.

Has anyone else experienced this?