Can no longer create deployment variables

I can no longer create deployment variables in pipelines via the Bitbucket console and all deployment variables previously created in all repositories have disappeared. This may have coincided with the release of the 'Deployment restrictions' premium feature (which is disabled)

Debugging in Chrome shows that the POST request returns a 404 when attempting to create the deployment variable:

#!http

POST: https://api.bitbucket.org/internal/repositories/<me>/<my-repo>/deployments_config/environments/%7Bbcc3b1f8-4d97-4cee-bdad-54bda407a9ab%7D/variables/

#!json

{"message": "HTTP 404 Not Found", "arguments": {"spanId": "086eca1d3138d1c3", "parentSpanId": "315bfee9a725c666", "traceId": "90f8245ac69b3264"}, "key": "Not Found"}

Without modifying every pipelines config file and passing in these variables some other way, I am no longer able to deploy anything.