Duplex mode (sort of)

Hi, I am trying to make 2 nodes that both send and recieve (ttl 1w). Node 1 mostly recieves form node 2 wich is sending periodically (around every 10 sec). But with a push button they can send their own message structure. This works most of the time. But i am having a problem (freezing of the reciever) when i think it sends/recieves to fast after each other and maybe the buffer isn't empty.I am using normal mode on both nodes. Do you have any tips how i can maybe clear the buffer or how i can handle this?