My four problematic custom Picklists reamain a problem.
The probability of a repro on your end in my circustances are low. This is because some unknown issue kept the editor from being able to subsequently open the custom Picklist. the only way for you to repro is to create, save, open, edit, rinse and repeat until you, too, get the backstore to misbehave as it did for me.
See my other concommitant Picklist issue reports for other details.
in any case, until we get actionable intel from the editor, assuming the problem stemmed from us, there's little and of us can do to fix this problem.
so this will be a thread that stay unsolved until some time in the future...