I think you are running into a similar issue that Iām facing (Bug: Request URI mutation when saving). Iāve resorted to saving the request and then copying over all the parameters into a new āunsavedā request when I need to use it.
Iāve been playing around with the pre-request scripts a bit and I think you might be able to resolve this issue by passing in the tail value (test) as a string stored in a variable by the prerequest script.
That sounds oddly familiar. Iāve been doing the same ācopy & pasteā method for now, but itās a B when you have to copy a bunch of stuff (body, authentication, etc.)
Iāll continue to monitor your thread as well to see if this gets resolved.
This problem still exists in version 10.23: I have multiple query parameters of which I only use one at a time. When I uncheck one and check another, a ā=ā is automatically added, invalidating the request.