I agree. It seems clear that somewhere along the line the unit was reassigned, probably before the fall of Danzig. I've seen this sort of thing before, there is an imperial order making specific assignments, but there are subtle shifts in the actual allocation of units. The disposition of the various 3rd and 4th battalions left in France to the 2nd and 3rd Reserve Corps is a case in point, Napoleon's orders do not match the final dispositions. could be a subsequent order went missing or didn't make the published collection of correspondence. or maybe the re-assignment was just a bit of admin work handled by Berthier for reasons unknown.
Thanks Daniel! Excellent stuff!