Marking as confirmed, adding the given URL fails with the following messages in rhythmbox' debug mode.
(14:39:47) [0x8bf1f68] [rb_uri_could_be_podcast] rb-file-helpers.c:809: 'http://spanishpod.com/lessons/feed/' should be Podcast file, HACK
(14:39:47) [0x8bf1f68] [rb_podcast_parse_load_feed] rb-podcast-parse.c:134: not checking mime type for http://spanishpod.com/lessons/feed/ (should be Podcast file)
(14:39:47) [0x8bf1f68] [rb_podcast_parse_load_feed] rb-podcast-parse.c:202: Parsing http://spanishpod.com/lessons/feed/ as a Podcast failed
Marking as confirmed, adding the given URL fails with the following messages in rhythmbox' debug mode.
(14:39:47) [0x8bf1f68] [rb_uri_ could_be_ podcast] rb-file- helpers. c:809: 'http:// spanishpod. com/lessons/ feed/' should be Podcast file, HACK parse_load_ feed] rb-podcast- parse.c: 134: not checking mime type for http:// spanishpod. com/lessons/ feed/ (should be Podcast file) parse_load_ feed] rb-podcast- parse.c: 202: Parsing http:// spanishpod. com/lessons/ feed/ as a Podcast failed
(14:39:47) [0x8bf1f68] [rb_podcast_
(14:39:47) [0x8bf1f68] [rb_podcast_
I'll report this bug upstream.