Hi, it seems to me that both versions are possible according to references on the internet.

http://dictionary.reference.com/browse/bandanna
http://en.wiktionary.org/wiki/bandanna

Do you have a reliable reference saying that "bandana" is the only correct spelling of this word? Thanks

I did not know both are considered correct. In my experience however, "bandana" is more commonly used.
The wikitionary entry for "bandanna" just states it's an alternative spelling. "Bandana" has a much larger entry.

I'd say change it to "Bandana", it is the more common expression afaik and it is even supported etymologically by the Hindhi "Bandhana" (not so much by the Tamil "Bandam"). Even though my browser's spell check prefers Bandanna...

We agree the variant with one "n" is more common, so the names have been changed. The change will take effect in Dev Branch probably tomorrow, Main Branch will most likely get it with the 1.52 update.