I haven't set it up yet, but I don't think it's over-shifting. The chain will shift into the second biggest cog, and then a turn of the pedals has the chain dropping off the chainring.
Odd. Could be different chain stay lengths causing the chain to now be slightly too tight, could be bb with throwing off the chain line. I'd start be redoing the derailleur from scratch and checking the chain length
I haven't set it up yet, but I don't think it's over-shifting. The chain will shift into the second biggest cog, and then a turn of the pedals has the chain dropping off the chainring.