Forum

Miyuki NAKAJIMA is two or three persons:

中島みゆき = NAKAJIMA Miyuki (Seiyuu/Vocalist, Wikipedia page)
Cast in Yosei Florence (movie) (1985, kanji source, is mentioned in her Wikipedia page)
Music (OP) in Cosmowarrior Zero (TV) (2001, Wikipedia page of anime, her own page doesn't mention the credit but the anime page links to hers)

中嶋美幸 = NAKAJIMA Miyuki (Animator, various readings but all persons at ANN with these kanji are "Nakajima" resp. "Miyuki")
In-Between Animation in Girls Bravo (TV) (2004, kanji source at D2_STATION)
In-Between Animation in Lamune (TV) (2005, kanji source at D2_STATION)
In-Between Animation in Akahori Gedou Hour Rabuge (TV) (2005, kanji source at D2_STATION)
In-Between Animation in Death Note (TV) (2006, kanji source at D2_STATION)
In-Between Animation in Gurren Lagann (TV) (2007, kanji source at D2_STATION)
Animation Check in Bakemonogatari (TV) (2009, kanji source at wiki.livedoor.jp)

中島美由紀 = NAKAJIMA Miyuki (Animator, various readings but all persons at ANN with these kanji are "Nakajima" resp. "Miyuki")
In-Between Animation in Super Atragon (OAV): (1995, kanji source at wiki.livedoor.jp)
Same profession but a considerable time gap of 9 years.

So at least a split between seiyuu and the first animator looks like a definite improvement; the credit for the second animator could stay with the first animator until better sources were available.