Gem Stash Bug

Since launch the skill Gem Stash hasn't worked right unless I am misunderstanding how it works.

I play on Xbox.

What's the difference between a base level and a gem level? Why are uncent gems a higher base level then cut gems?

When I engrave a skill Gem from my stash with the 'sort by items' set to 'base level' it drops it's base level to 1 and drops it to the bottom of my stash where it is a complete mess full of other gems that are engraved.
Why does engraving a gem change it's base level to 1?

If I set the sort to Gem Level the levels are correct but the sorting is done by individual levels anymore making it look like even more like a huge mess.

Also can we have better sorting options with the gem stash? Like a Mace Filter or Quarterstaff Filter?