Bug report

Bug summary

The colormap/tick locations within the colorbar are not being updated properly with a SymLogNorm on master. I think this is different than #16269 because it is actually creating the colorbar, just a wrong one.

Compare the previous correct version:
https://matplotlib.org/3.1.0/gallery/userdemo/colormap_normalizations_symlognorm.html

with a fresh checkout of master:

Difference in the colorbar of the top axis.