I tested this out on my camera. If I use the Fn1 or Fn2 buttons to make changes on the Live screen, go to the Settings screen, then back to Live, my changes remain and the displayed values are still correct.
If I use the Fn1 or Fn2 buttons to make changes on the Live screen, go to the Settings screen, then go into the Menu, then back to Live, my changes remain but the displayed value is also correct.
If I use the Fn1 or Fn2 buttons to make changes on the Live screen, go to the Settings screen, then go into the Menu, then back to Settings, my changes remain but the displayed value is incorrect.
I ran a couple tests:
My shutter starts at 180° and in the Live screen I use my Fn button (Shutter-) to change it down to 45°. I go to the Settings screen and then back to Live and it still shows 45° (and is appropriately dark). But if I go to Settings>Menu>Settings (or Live), then the shutter shows up as 180° on both the Settings and Live screens even though it is clearly still set to 45°. Clicking the Fn button to shift up or down again will then jump the shutter up or down one increment from the 180° setting and now displays both the correct shutter value.
When tested with the FN assigned to ISO-, I start at 1600. In the Live screen I click the Fn button until I’m at 400. I go to the Setting screen (where it says 400) and back to the Live where it still correctly displays 400. If I add in the Menu step again (Live>Setting>Menu>Setting) then the displayed value jumps back to 1600 upon leaving the Menu and in the Live screen I can clearly see that it’s still at 400 ISO levels of image brightness even though the on-screen value is claiming 1600. As with the shutter, if I then click the Fn button it will make the change based on the claimed 1600 value (at which point it will properly show the 1250 value as well as actually using that corresponding setting).
So my findings are:
Live>Settings>Live - the displayed values stay correct
Live>Menu>Live - the displayed values stay correct (unless I then access the Settings page afterwards)
Live>Settings>Menu>Live - the displayed values are incorrect
Live>Menu>Settings - the displayed values are incorrect
So it seems accessing both the Settings and Menu pages after having used the Fn buttons to make changes is what causes the issue, as Live to/from just the Menu or Live to/from just Setting does not trigger incorrectly displayed settings nor does accessing the Menu after going to the Settings page (as long as I skip returning to the Setting page and go directly to Live), but as soon as I access the Setting menu at any point after being on the Menu page the display error will occur.