I believe the metadata uri returned from the REST api for event receivers is incorrect. The uri is in the format:
which is invalid. The correct uri should be:
If this is true, how would you report this bug?
Event Receiver Invalid URI
I wanted to add a screen shot to help explain this. Above is the raw output from the REST api:
The "id" which is equal to the __metadata.uri value is incorrect. On a side note, I wrote a blog post of adding event receivers using the REST api here.