When analysing the 2015_in_sports article on the English Wikipedia it encountered a link to http://www.la2015.org/results-filter twice. On line 1,848 it marked it as permanently dead, on line 4,282 it rescued it with this archive link.
Diff of edit.
I am unable to replicate this problem. It may have just been a glitch. IABot does use learning algorithms to improve itself.