That was a very different situation and building bridges does take time. When Napoleon decided at the end of the first day's fighting/early on 17 October to withdraw from Leipzig, the operation was going to begin almost immediately. There was neither time nor opportunity to build bridges over the Elster to get the army out. Further the terrain over which a bridge or bridges would have been built was swampy terrain and there was no time to begin or complete what would have been a major engineering project, much different from the situation in November 1812 at Studenka.
Further, at the beginning of the action, Napoleon's line of communication was based on the Torgau-Wittenberg-Magdeburg fortress complex, and the Erfurt road was only an alternate line of communication. That was why Napoleon's combat trains were at Eilenberg north of Leipzig instead of to the west through Lindenau and Erfurt.
The withdrawal began at 0200 on 19 October. I don't see how any major bridge-building could occur. It took some time to build the Berezina bridges, and they were not the best product, though they sufficed.