Switching to "Stable (.NET 4.x Equivalent)" breaks Animation Editor

Easy to reproduce:

1. Create an empty Unity (2018.1.0b13) project and open "Edit" =>> "Project Settings" =>> "Player" menu
2. Set "Scripting Runtime Version" to "Stable (.NET 4.x Equivalent)"
3. Restart Unity
4. Drag a mesh into the scene (cube or anything)
5. Open animation editor ("Window" =>> "Animation")
6. Click "Create" animation clip button
7. Animate something with a negative rotation value. Unity will not accept the entered value and overrides it with some other weird number. You can see this as soon as you preview your animation.

Case number: 1027800

 

Please post a case number if you have one - is it specific to 2018.1 beta, or does it happen in previous versions?

 

I'm sorry. I've just tested this in a fresh empty project and the issue was gone (2018b13). My project must be corrupted or something.

 

OK - if it occurs again please use the bug reporter tool and Unity will take a look

 

Okay, the issue only appears after switching to "Stable (.NET 4.x Equivalent)". I've updated the first post and made a bug report with case number 1027800.