It takes a little while for the support server to come back to re-index the map. I updated the DB directly to speed that process up, should appear fixed now.
triplea_support_server=# select map_name from map_index where repo_url = 'https://github.com/triplea-maps/ww2v5_variants';
map_name
----------------------
world_war_ii_v5_1942
(1 row)
triplea_support_server=# update map_index set map_name = 'ww2v5_variants' where repo_url = 'https://github.com/triplea-maps/ww2v5_variants';
UPDATE 1
triplea_support_server=# select map_name from map_index where repo_url = 'https://github.com/triplea-maps/ww2v5_variants';
map_name
----------------
ww2v5_variants