Looks like a recent merge of RKRequest introduce this the following bug.
1. create a RKRequest
2. send asynchronously
3. received result from server
4. after the timeout period (default 120 sec), get notify from RestKit that a timeout has occurred.
I looked into the recent merge and it seems like that a NSTimer is created in sendAsynchronously before calling fireAsynchronousRequest which in itself create another NSTimer. Therefore, 2 timer is created even though we only need one. I commented out the first NSTimer creation (line 426 in RKRequest.m) and everything worked fine again.
Thanks for pointing this out. This was being discussed over on the google group as well. I'm committing a test and patch and am going to put in a pull request to fix this.
Remove duplicate timer creation. Fixes #517.
Fixed in development, will be merged to master soon.