Hi 
 
I have experienced some bugs on new update 2018.09
 
one of the major problem I have now when Edit clips and automation.
 
1. When split clip, clip(s) do not split at Now position. (it split unexpected position)
2. When copy and paste track automation lane to other position, automation data do not paste tack I would like to. (it paste unexpected position and track)
 
I have this problem in almost done mix session.
no problem with Editing at starting of the session.
 
It may appear when a project is large.
 

How are you trying to split? There are several ways.
 
If you are using the Alt key (hold Alt down while over a clip and scissors appear) method, then it will split according to the Snap settings closest to where your mouse is, no matter where you mouse or now time is. 
 
If your placing the Now Time at a certain spot and then right clicking the clip and choosing 'Split' there and it's not splitting at the now time, then try doing it in a new project to see if it's project related. Because it works as expected on my system.
 
 

Have you accidentally left the snap to option on?
 
Is it possible you need to zoom in closer to clearly define the edit point to the software?

2 are my most do functions.
so no possible on the problem of the way of use.   
 
Yesterday, new Windows update was installed automatically.
After then, now, it fixed. Is it possible????
split multi clips better faster and copy paste automation data too. very strange....