Inventory Bar (last square)

I am having issues with my Minecraft pocket edition, inventory bar. The last square on the right doesn’t want to switch. I can put new items in it but select the actual square and it won’t change. It will remain the last square I had selected. I can sit there and press it twenty times and it still won’t switch. It will appear for a split second and then it goes back to the last square select. I thought it would have been fixed in the newest update. But it appears not. Is there something that I can do to resolve the issues, and is this issue occurring with others as well??