I encounter the same issue and I’m surprised too.
Workspace with the spec, collection and environment.
The “1. openEHR REST APIs” collection is a custom collection that shows what I want to achieve.
The “EHR API” collection is generated and shows the :var (e.g. :ehr_id) pattern that makes it cumbersome to map to environment variables.
workaround:
In the end I ended up exporting the collection to GitHub. This gives me a json file. I then did a search and replace of :var with {{var}} and imported this to postman as an replace on the collection (just committing to GitHub get’s overwritten by postman, instead of syncing changes from GitHub to postman).
I also tried find and replace using postman, but somehow my collection is read-only from the find interface (I can edit using the main window..) seems to be a known issue: Collection becomes readonly in the Find & Replace and can't be changed · Issue #12144 · postmanlabs/postman-app-support · GitHub
Postman
Did you have any updates? I think this would be a sensible change to GitHub - postmanlabs/openapi-to-postman: Plugin for converting OpenAPI 3.0 specs to the Postman Collection (v2) format