Spider projectiles crashing into the ceiling

We've seen it too with the Warden's shrooms, just flying to the ceiling of non-open maps. They have to have a reduced flying arc.

 

And now that we're here, you can also see the annoying smoke of the Siren's projectiles too, if we can fix this it would be much appreciated.

Is that on Arcane Library? If so, I believe that is just a consequence of how that defense works. Like with any map and the defense you are using, you need to consider how a defense placed in that location will work. 

Reducing the arc may help on that map but may be hurt the defense when considering placement on other maps that have structures you want the spider to throw them over.  Adjusting the arc based on where it is placed would remove the unique nature of the defense.