I have posted about this before and still not addressed.
Currently Rekordbox is very unwieldy in the 150 bpm and 75 bpm range.
Mixing 75 bpm to 150 bpm causes a 50% increase or decrease in pitch AND switches tempo slider to master tempo i.e. +/- 100%. There isn't a predictable way to correct the tempo on the master/live deck after this happens. Correct by mixing to closest MULTIPLE of master tempo and allowing relative tempo change. Also the pitch slider should not "catch" the new tempo, it should speed up or slows down relative to wherever the track is at.
Rekordbox staff please look at how serato handles sync/master tempo and quantize features. They really did a good job of preventing unpredictable behaviors. At minnimum you guys should have a feature to disable the automatic switching between 16% and 100% master tempo, it is so frustrating!
A more minor issue is looping, which has been partially fixed. Currently when a loop is active, only the looping track allows pitch bend. The other track you are mixing in does not respond to pitch bend. This should be easy to correct by allowing pitch bend on both the active loop and track you are mixing in. I will note that prior to 4.1 NEITHER track would pitch bend when synced, so thank you for that fix.