If you start with an empty part and just add a single Connective Pattern, initially it starts out with "Limb" set to "Perc 3R", and at the point it is showing on the "R3" row, as I would expect. However, any attempt to change the "Limb" setting results in it showing on the wrong row afterwards, as follows:
Perc 1L = Doesn't show up at all, but still plays
Perc 1R = Row L2
Perc 2L = Row R2
Perc 2R = Row L1
Perc 3L = Row R1
Perc 3R = Row L3
I don't use Jamcussion quite as extensively as I use the main drumming tab, but unless I'm completely confused I think this is the wrong behavior.
In all cases, it seems to play as expected, although the case of "Perc 1L" not showing up at all it presents a problem if you want to manually edit the pattern.