Easy to reproduce:
1. create a new Lesson
2. in the Lesson edit form set the "Maximum grade" to e.g. "10"
3. go to the gradebook and choose "Show ranges"
4. see the grade item for the new lesson
What is expected
You should see range 0-10.00 (or whatever you have set)
What actually happened
the range is still 0-100 and you are not able to change it
Setting high priority for this as it makes lesson grading not backward compatible with 1.8 behaviour. Assigning to myself - I'm going to look at it.