On Plasma 5.8 beta, the plasma tooltips have a weird behavior. i'll try to explain : Smooth transition works now on Wayland, BUT there is one thing wrong : they "remember" the last position of the tooltip when they shouldn't. 

I mean : if you hover the mouse pointer on the clock in the systray for example, the tooltip shows the time and date, which is fine. Then if you move your pointer away, the tooltip disappears, which is good. But now, if you move the pointer to another element of the panel, a launcher (icon) for example, this is where the weird thing happens : on X11, the tooltip appears on the icon, which is the expected behavior. But on Wayland, the tooltip remembers last time it was on the clock, and then, it slides from the clock to the icon (unexpected behavior). The tooltip should just pop up on the icon like it does on X11 instead of sliding from the last element.

Reproducible: Always

Steps to Reproduce:
1. Open a Wayland session, put mouse pointer on systray
2. Move pointer to the wallpaper or a window
3. Move pointer to another panel element (example : the K menu or a launcher)

Actual Results:  
The tooltip slides from the systray position to the K menu or launcher

Expected Results:  
The tooltip should simply pop up on the K menu or the launcher.