When creating a Transition between 2 states, the default Duration is 0.25
This works fine on clips with animation on the transforms, but defaults to an incorrect value of 0.1 when the State does not contain a clip (empty state) or contains a single key on a blendshape, for example.

repro1 (empty state):
-create an Animator Controller
-create two new empty states (Create State > Empty)
-create a Transition between the two states (RMB-click the first State > Make Transition, click the second State)
-select the Transition (line between the two States)
-expand Setting in the Inspector...
Bug: Transition Duration = 0.1
Expected result: Transition Duration = 0.25

repro2 (blendshape clips):
-Import attached package (or any animation clips with only one blendshape key)
-create an Animator Controller and add two of the FaceClips
-create a Transition between the two clips
-select the Transition (line between the two States)
-expand Setting in the Inspector...
Bug: Transition Duration = 0.1
Expected result: Transition Duration = 0.25

found in all versions.