Removing the quotes around the split_dir in the arguments, just in case. Seems to work

shared/workspaces/alembic/versions/templates/pims_split/split_condor_2.8.3.txt

 executable = split.sh
-arguments = "$(split_dir)"{{#quicklook_url}} "$(quicklook_url)"{{/quicklook_url}}
+arguments = $(split_dir){{#quicklook_url}} $(quicklook_url){{/quicklook_url}}
 
 output = tiles/$(split_dir)/split.out
 error = tiles/$(split_dir)/split.err