Flight Director Gene Kranz speculated that it could have resulted from extra air pressure in the docking tunnel, or a result of Eagles pirouette maneuver.
flˈaɪt dᵻɹˈɛktɚ dʒˈiːn kɹˈænts spˈɛkjʊlˌeɪɾᵻd ðˌɐɾɪt kˌʊdɐv ɹɪzˈʌltᵻd fɹʌm ˈɛkstɹə ˈɛɹ pɹˈɛʃɚɹ ɪnðə dˈɑːkɪŋ tˈʌnəl, ɔːɹ ɐ ɹɪzˈʌlt ʌv ˈiːɡəlz pˌɪɹuːˈɛt mənˈuːvɚ.