sounds like a memory cache'ing type of issue, where the unit (or any device in the system) is still processing the previous command when the next one comes in...explaining what you're trying to do/accomplish would be a better way to get responses and results.

ie, if you are trying to repeat a volume (or navigation or channel) up/down/left/right type of command say this is what you're trying to do, and list the device/model number of the device you're trying to control.

it could be that your control system is fine but your end device can not process 'x' number of inputs/commands in 'n' time period. You've done well to try and give us lots of information, but without the right information its hard to help.