Another one for you from Beta 6.5.0.701 for Mac: It's not possible to rename Sections within an Item.
STEPS TO RECREATE:
1) In any Item, Edit, then click [Add Section] and move it where you want
2) Click in the name of the section and type its new name
3) Hit TAB or ENTER or click out of the field — note that the name you gave the item remains
4) Save
5) Edit
RESULT: The new section is back to being called "SECTION"
6) Rename any existing section, repeat steps 3,4,5
RESULT: The renamed section is back to its previous name