You probably accidently sold the korambits and just happened to have some white ones lying around in your inventory ;_;. There is no way they got changed.
wouldn't say 'no way' since most of the early responses to bugs turn out to be overtly negative and rather vehemently opposed to any suggestion of a bug.
So can you substantiate it at all? What was the last time you saw it before the change and when exactly did you notice the change.
Do you have heroes you might have put it on, etc.
Might be best if you just report it to support and see what they have to say since they are really the only ones with the proper data to confirm or deny this claim of yours.
You probably accidently sold the korambits and just happened to have some white ones lying around in your inventory ;_;. There is no way they got changed.