Just to clarify we are aware blueprints are not the correct way to separate devices: How can I deploy updates to different blueprints from the same image We do have different hardware for dev devices to live so should probably never have an OTA which does not specify the blueprint.
We did this because we experienced issues with updates not being received by devices but recently found that this was the start rollout button. If we had an OTA which immediately started the rollout it would not be picked up by devices but if we started it paused and used the toggle button it would updated devices right away. Not sure if this is something our end or yours.