Difference in simplepie between curl and fsockopen?

Question

I use the contao CMS, which uses SimplePie 1.3.1 for fetching rss feeds. Fetching a feed on my development machine worked perfectly but it did not work anymore on my production machine. Following the execution, on my development machine it uses fsockopen while on production it uses curl. When it uses curl I can see that my url http://foo.com/o/index.php?page=search&sFeed=rss is changed to http://foo.com/o/index.php?page=search&sFeed=rss# (fragment identifier is added) when going through SimplePie_Misc::compress_parse_url in SimplePie_File constructor. The problem is then than curl doesn't get the right page. (I can't force fsock as it is not part of my own code). Is there something that I don't understand or a bug ? (but it seems odd as my url is quite common)