You need to turn on the tx first then the rx second.

I have seen my receiver do this when I have no tx on, but not always.
You should always turn on the tx then the rx and in reverse turn off rx then turn off tx. Safety precautions!!
Might be picking up surrounding rf noise as these are not the most selective receivers.

I found out their is a guy in the neighbor hood that has a park flyer he flys in my area and we are on the same channel.
His free time is about the same as mine. This lends a problem with the park flyers not needing a regular field.
Their is no frequency control with the park flyers in any area unless at a field. Could be a new problem for ama.