Found a bug with data variables … I data element that I previously set up is showing parameters as obsolete.
This is a recent issue since I initially set this up a few weeks ago and it was working fine.
Checked the data setup and all parameters are set to required.
It only appears to be this one data variable.
Interestingly, this particular data element does not have a data schema as it only returns a value.
Submitted bug report here.
To solve this problem I rebuilt the data resource from scratch in the data configurator. Parameters are now appearing. Not sure what caused this to break in the back end.
I very rarely use built-in Rest API data sources anymore because of things like this. I do pretty much everything using custom HTTP Requests (which btw permit using PATCH). And i just build out my own object variables to whatever schemas are required. It just gives me more flexibility constructing my data flows by hand.