Well you got me that's for sure? I've seen some fun things like the TX and RX not linking up for more than three minutes out at the field but it's not a regular thing. I've never though seen an RX lose the bind completely, heard about it, never seen it myself. At least that's never happened at our field.
Hate to ask but you aren't pushing any buttons like bind buttons when you shouldn't huh? LOL
Also curious once you've binded the model if you switched everything off and back on is it still fine?