pyproj version 3.6.1 has a bug where trying to set crs will result in a crash stating TypeError: expected bytes, str found
The issue appears to boil down to changes in cython which pyproj resolved in version 3.7.1.
pyproj issue reported here:
pyproj4/pyproj#1451
pyproj resulting fix here:
pyproj4/pyproj#1452
Proposed solution is updating pyproj dependency to 3.7.1.