If the file is originally 48 khz then played back at 44.1, it will play slower and lower in pitch, while a 44.1 file played back at 48 khz will be faster and higher in pitch by about 1.1 notes. Look at the conversions performed before the file was uploaded. Chances are you had a 44.1 khz wav file converted to 48 khz somewhere down the line without proper sample rate conversion performed, then was converted to 44.1 mp3 with sample rate conversion.