OS: Windows Vista SP2
Version: All builds this year up to 2.2.0 10-apr-17. Does not happen in 2.1.3-alpha-27-jul-16. Can’t say exactly when it started - guess I liked that July rev too much.
I always download the zip file, copy portable settings into the unzipped folder on the desktop and run Audacity from there so I can compare revs when I have to.
No special procedure needed to reproduce this, just display History after loading a project and applying some effects, editing, etc. Attached is an example of what I mean.
I agree it is confusing, but it is by design (and I was out voted).
The “size” numbers represent the amount of disk space that will be recovered when using “discard levels”, not the amount of space that was used when doing the listed command (so not the amount of space that will be recovered by “undoing”).