A few days ago while trying to rearrange our Campaign classifications, I found yet another SiteCatalyst conversion classification editor issue.
You can’t date enable a classification, and by the way disabling an already date enabled classification won’t work either.
I do think the Conversion classification editor has been having quite a few issues lately.
Workaround:
As usual, switching back to the SiteCatalyst 13.5 GUI while performing administrative tasks is a possible workaround.