Reply to Traktor BPM Problem!

Along with DJing , I spend the majority of my time producing music!

I made a track that begins at 128bpm , and is 128bpm for approximately half the song! But on the second buildup, the BPM slowly increases and the song drops at 140bpm (hardstyle drop), then the outro is back at 128! I can never get the intro of one song to sync with the outro of my song because the grid in traktor is off!

One time, I load the track into traktor, it reads it as 128bpm , another time, it says the track is 189bpm

Help?