HELP Some tracks not warping correctly to BPM

I’ve been having this problem where some of my drum samples are synch to my projects BPM and some are not. Sometimes, the same sample in a different song will not synch correctly. The sample will, sometimes, synch much slower than the bpm of my project. Sometimes it’s just completely out of wack.

I import the sample from a song via a aifc file. I then take the portion of the song I want to sample and mix that portion down to a WAV file. I have snap and music mode on the entire time. I then drop that new sample onto the track. I then go into the sample editor and hit music mode. Sometimes the sample will change perfectly to the BPM, sometimes it’s too slow and sometimes its just way out of wack.

Am I doing something wrong?

Drum clips should sych to my BPM pretty easily correct?

Is there perhaps a glitch in Cubase Artist 6?

Or is the glitch in my brain?