I reported a bug a while ago that I couldn't Sprint jump and was bugging me.so I went back for retesting on my tablet using the physical keyboard then I realized that I couldn't Sprint jump if I used my sprint key which was Ctrl but if I double click on any directional button (WSAD) I could sprint jump as well using the screen, so all though I seems like it may not get fixed I hope it does in future updates. THANKS and best of luck in future endeavors
This is a hardware limitation of some keyboards, see MCPE-171010.