Using the Comm example in the ConnectIQ Sdk (connectiq-sdk-win-2.3.4) and the the Comm example on Android (connectiq-mobile-sdk-android-1.4) with the simulator I always get double statuses for transmissions. First a SUCCESS then right after that a FAILURE_UNKNOWN.
The only modified part of the android code - by me - is this:
mConnectIQ = ConnectIQ.getInstance(this, IQConnectType.TETHERED);
So that it uses the simulator.
At least one more user reported that it happens on real devices too (https://forums.garmin.com/forum/developers/connect-iq/1265763-questions-regarding-communications-api-and-transmit)