In Version 1.90 I had no problems with Pinch or Crease with DynTopo.
I was always able to create sharp edges as shown in the clip.
Now in Version 1.91 I can no longer create sharp edges.
Are you having this problem too ?
Known issue
Hello, if you use crease with dyn typo on body layers and than unseen or worse delete that layer with crease, it will mess up the original body too… 
It’s the same issue, if the topology is messy, the layers will struggle.
Hello Stéphane,
Here is the clip from the Version 1.90.
The edge is sharp as it should be. The Problem also existed in a previous version.
You fixed it then. Now it is back again.
But i am sure you will fix it 