OK, I understand the bug that Xach found:
There was an ancient bug whereby input-files for a module always returned a singleton list containing the module's component-pathname, its directory. That wasn't an issue then due to the even greater deep design flaw of timestamps not being propagated. Since the latter bug was fixed, the former popped its ugly head. Because SB-ROTATE-BYTE has a module (a fake one for the purpose of using :if-component-dep-fails), ASDF wanted to recompile it, which fails. If you have a fast compiler and you don't install, the entire thing can be compiled in under a second, and the timestamps for all the fasls and directory are the same. But after you install, the directory timestamp is older, and you are sure to lose.
Anyway, this should be fixed in 2.26.33.
My apologies for the breakage. Software is hard.
—♯ƒ • François-René ÐVB Rideau •Reflection&Cybernethics• http://fare.tunes.org Truth comes as conqueror only to those who have lost the art of receiving it as friend. — Tagore