I have a Sansa E260, and my girlfriend has a C250. Sometimes on both of them, they get into a state where the left-pointing button goes forward towards the future tracks in the playlist instead of backwards towards the beginning. I can then reboot and it works better, although the display does strange things. Also, occasionally it spontaneously plays a track twice.
The strange display: when the problem happens, the correct track info is displayed for a fraction of a second, then the next (incorrect) track is displayed. After a reboot and I hit "play" then "pause", when I try to go backwards, the next track is displayed for a split second, then the correct one. Going backwards again (left arrows) will show an even later track, then the correct one. For example, if I was on track 100 and wanted to go back to 99, it would display 99, then 101. Back again would show 100, then 102 (IIRC). Reboot (sets automatic bookmark), play, pause, back shows 103, then 101. Back again shows 104, then 100. Again shows 105, then 99 and I hit play before it messes up again and it plays track 99. I will pay closer attention next time it happens to verify that this really is the behavior.
Each of us are listening to a audio books that have short tracks: about 45 seconds per track. We usually use Ogg/Vorbis, but I tried MP3 in hers to see if the problem still happens, and it does. Also, we usually have the tracks on microSD cards, but I tried it on hers with the files on the internal flash, and it still failed. This has been going on for a while, although it seems like there was a version of firmware late last year that didn't have the problem. It seems to happen most often to me after playing several dozens of tracks, so it has been difficult to determine exactly when it happens or doesn't.
The latest time it happened was today (oops, yesterday now; it's after midnight) with version 16362 with USE_ROCKBOX_USB defined (cool feature, BTW) on my Sansa E260. Annoyingly, it happened to me 3 or 4 times today in about two hours of play.
Perhaps unrelatedly, but still annoying, not infrequently when playing a list of MP3 podcasts, especially when trying to go back to previous tracks, the display claims that the track is APE instead of MP3 and the total track time is 0:00. It usually plays OK, but sometimes plays the wrong track in the playlist.
Also, since my E260 is refurbished and the screen cover cracked, I bought a second E260 and the C250 for my girlfriend. I thought the problems I was seeing could be because of refurb hardware. But no, since it happens on all three.
I apologize in advance if these problems have been described before, but I couldn't find them listed. I have a hard time believing no one else has seen these happen, since they occur so often to me and my girlfriend. Does anyone else see these problems? Should I just live with it, or should I start investigating the source code? BTW, I'm sorry for the length.