Yeah, it's human error. TBB doesn't leak anything to your clearnet browser on its own. It could be exploited of course, but in that case the attacker would aim for more interesting targets anyway, like we saw in the FH attack. He might grab your MAC address and send that with your IP address to a phone home server. The biggest problem with the SR community is they believe Tor is only for hidden services. and clearnet links should be copied to clearnet browsers. That's not true! Any link you find on the darknet should be viewed only over Tor.