Error: BPM sync on. Turn sync on --> off to Beat sync again

Hello, I play track A in the left-hand desk and track B in the right-hand desk. Both tracks are set to 150 BMP. After the transition from track A to track B and at some point in the track B, which is currently playing, I change its BPM number to 145 BPM in the software and hit enter in my laptop keyboard, that part of the track then changes its tempo to what I want. The BPM numbers of the two desks then change to 145 BPM and the red light of the Beat Sync buttons of the two desks are turn on. The problem is that after I load another track (track C) into the left-hand desk and hit play at the set cue point during the transition. The BPM is not sync even thought the Beat Sync buttons are turn on. And I receive this error on the software screen. https://www.dropbox.com/s/vfg1m0pwo5q47bt/IMG_20200710_141344.jpg?dl=0 The two songs are not playing at the same tempo. The Recordbox software version is 5.8.5 and my controller is DDJ-400.