Success callback triggered before failure buffer pops

[jdenen]

1. Favourite a toot
2. Favourite again

You'll get the successful feedback:

Favourited #12345

And then a buffer:

HTTP/1.1 422 Unprocessable Entity
Date: Sat, 22 Apr 2017 20:53:01 GMT
Content-Type: application/json; charset=utf-8
Transfer-Encoding: chunked
Connection: keep-alive
Server: Mastodon
X-Frame-Options: DENY
X-Content-Type-Options: nosniff
X-XSS-Protection: 1; mode=block
X-RateLimit-Limit: 300
X-RateLimit-Remaining: 299
X-RateLimit-Reset: 2017-04-22T20:55:00.151905Z
Vary: Accept-Encoding, Origin
Content-Encoding: gzip
Cache-Control: no-cache
X-Request-Id: bee31336-e2c2-4208-aa47-c22c131d7044
X-Runtime: 0.059796

{"error":"Validation failed: Status has already been taken"}

[jdenen]

Spun off of #55