It seems like this problem only happens on really long podcasts.
Today I was listening to a 90+ minute podcast. I wanted to re-listen to something. I rewound to the 1:15 mark, but that was too far. So I fast forwarded to the 1hour:30minute mark. When I released the FF button, the podcast reset to the 0:00 mark. On about my third try I finally made it to the 1:30 mark by FF to the one hour mark, then bumping forward only a couple of minutes at a time, while releasing the button between each try.
Then, I finally got to where I wanted to be, and continued listening for a few minutes. I paused the Clip. The clip powered down. I turned the clip back on, and when I pushed PLAY, the Clip reset back to 0:00. Aarrggh.