Multiple display issues under the "perspective mode"

Multiple display issues under the "perspective mode", Are these some kind of well-intentioned functional design?

The visibility of the sketch is completely random depending on the point of view.  

I know the only way to avoid these is to turn off the "perspective mode". But what confuses me is why? 

Example 1: round corner disappeared

Example 2: a simple circle disappeared

if there is no center mark or filled color, you can not see the sketch at all, just like the "round corner" example above

Example 3:

In fact, it's much more than that, if you use the "delete segment" tool under the "perspective mode", it will cut the segment When your mouse doesn't actually touch or hover over that line segment.

It's like they told you that every building within 1 km of the factory will be demolished, yet your house is 1.5 km away and it's still being demolished