Content consumer fails to build if default-provider snap isn't on stable

Hi, I’m experimenting with a content snap that isn’t yet ready to push to stable. If I specify it as a default-provider in a consumer snap that then fails to build with:

error: snap "mesa-core20" is not available on stable but is available to
       install on the following channels:

       edge       snap install --edge mesa-core20

       Please be mindful pre-release channels may include features not
       completely tested or implemented. Get more information with 'snap info
       mesa-core20'.

I don’t see why this fails at build stage: I see no reason for the build to be installing the default-provider. (I can see reasons it might fail at a later stage, but surely building locally ought to be OK.)

There are two ways I can workaround this: either don’t specify the default-provider, or explicitly specify the edge channel:

plugs:
  ...
  egl-libs-core20:
    interface: content
    target: $SNAP/egllibs
    default-provider: mesa-core20/edge

For reference, this is the consumer project:

Channel edge would not be supported on the snapd side. I would remove the default-provider for now as technically, there isn’t any (required to be on stable).

On the Snapcraft side, it is used to verify that all libraries can be resolved, there is a forum discussion I can fetch from a couple of years ago where this was discussed.