Still happens for me, but a lot more sporadic now. Maybe 1-2% of the time. Sometimes starts in middle, sometimes 30 seconds to a minute in. I'm assuming something's funky with the database for tracking where you last listened to a podcast (maybe it's getting confused and using the same value for multiple podcasts). Since I'm listening all the way through on most things, there's probably not many podcasts half listened to on my i4.
BTW, I haven't seen this with video podcasts, just audio.
Possibly unrelated, I've also noticed podcasts and songs with the wrong album art on the i4 after the 4.1 update.