Is anyone else having an issue with Unity moving GameObjects around when loading scenes?

This seems to be happening exclusively with UI objects. I have two different scenes that are being affected in this way.

This just started after switching over to 2018 so I could use ProBuilder, but interestingly enough didn't start happening until a few days after I made the switch.

If I load up the scene in the editor, my UI object which should have x position 100 is being moved up to 210 and some odd digits. I move it back down to 100, save the scene, open another scene. Now if I open up the first scene again, the object is moved back up to 210 and some odd digits. I haven't run the game or changed anything else. This is happening in multiple scenes with multiple UI objects.

If I save the objects' positions, switch to another scene, and run the game from there, then when the scene is loaded in the context of the game, the objects' positions are correct. But if I load up the scene in the editor again, the positions are all off and running the game at any point after that reflects the wrong positions.

EDIT: I added a gif showing what's happening. You can see in the gif that I ctrl+s after I make the changes (the star on overworld disappears)

EDIT 2: Seems to be a problem with setting my HUD to Screen Space - Camera. The problem doesn't happen if I set to Screen Space - Overlay. I think for my particular needs, Overlay works fine, but I'm not sure why this is suddenly broken.

EDIT 3: On my second scene, Screen Space - Overlay is the one that's broken: It pushes all of my UI elements into one big pile at the center of the screen regardless of how I place them in the editor.

 

It's probably this problem (fix is going to land in 2018.1.0b10):
https://forum.unity.com/threads/beta-5-recttransform-anchors-pivots-broken.515296/

If you believe that's not the problem, please submit a bug-report, following the advice given in this document and post the Case number here.

Spoiler: Full version

If you found a bug in Unity, it's recommended to submit a bug-report following the advice given in this document.

Using the bug-reporter seems to be an important step, because it makes sure the report is in Unity Technologies bug-tracking pipeline, has to be processed at some point and you can kind of track if it's fixed. Using the forum is often used to add to a little more attention to a bug-report, but does not replace submitting the bug-report.

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