MCPE stops jumping with BT Keyboard and mouse shortly after I start to play MC

I just bought MCPE . Since the controls are slow on touchscreen , I use a BT keyboard and mouse . I start to play MC , but shortly after I commenced playing , Steve does NOT want to jump whenever I press the space bar . The battery level of the keyboard is full , and it is in perfect condition . I even tested it in the notes to see if the space bar works , and it did perfectly . I restarted the game , and it worked perfectly until it happened again . Then i restarted it again ... it happened again . I thought that MC stops registering the space bar , but 1 time when I was playing in Jartex , I double-pressed the space bar . I did not jump but the server said that i can't fly . This happens in all the worlds . Pls help me however you can . [added after 4 hrs] I just noticed tht if i stop jumping for more than a few seconds , this problem occurs