I confirm the remark about the timeline disappearing on Android. In certain situations if you hit back (or swipe from the outside of the screen in to do the "back" gesture) the timeline just disappears and there is no apparent way to activate it again. The only workaround I found is to switch to Satellite view which has its own timeline, then switch back to whatever layer you were initially on to bring back the timeline on that layer.
Another bug (?) I noticed with the route planner is that if you type in a custom speed and tap the "enter" key (as it's the most intuitive way to exit the keyboard input field) the whole route is reset. The workaround would be to type in the custom speed and then tap outside the keyboard window to make sure the route is kept. However this is not at all intuitive...