Comment # 2 on bug 1231363 from Jan Engelhardt

Created attachment 877788 [details]
screenshot 2

Deleting the swap partition reveals that "at least 17.5" translates to "19.99"
for some reason - and then fits the disk exactly.

As the btrfs partition is marked for automatic sizing, it would appear that the
final size derivation for the root partition failed to discount the swap
partition's size. That, or the 'at least 17.5' is too generous, in the sense it
should be 'at least 1.6 GB' (size reported under "Software" notebook page).