Do you try to send data to different devices from a 433mhz transciever? Then you should configure your setup a little bit differently, IMHO.
You should only have one thing for the transmitter and use a reentrantlock to prevent concurrent access to the transmitter. E.g. when you switch two devices in short time. So both switches will try to send data with the single transmitter at the same time, this will not work.
And sometimes the end of the transmission takes some time, so waiting after each send command is necessary.
And it is also good to read back the return value of the execution to see when things go awry.
Maybe you can adapt shown things from here.