I also seem to be having a similar issue
I've been streaming fine for months, barring ISP connectivity. However, as of yesterday, 1/14/2015 OBS is dropping frames to Twitch for whatever reason I do not know.
I obviously thought my internet was the culprit because it always is. However, this time Comcast was not to blame, at least not as far as I can tell. Everything was, and still is, perfectly fine. However, OBS is flashing red and yellow, and is consistently dropping 50% of my frames.
Ideas? I've double and triple checked all my connections, all the OBS settings, everything is exactly the same as its always been. I even tried changing server locations, from Miami to the Texas one. Still nothing.
Really sad right now.
[EDIT]
http://www.teamliquid.net/forum/tech-support/326034-jtvping-find-your-best-twitchtv-server
As I stated above, I tried the Texas and Miami because they're geographically closer to me. I went to that link and downloaded that little application, and it showed that the VA server was actually best for me at the moment. I tried that server and my issue is gone.
So my issue is fixed temporarily, however I'm still quite confused as to why all of a sudden my drop in connectivity happened.