Bot to register user that made changes to column

[CoreWand]

I made a bot to keep track of which user edited a specific column and it works like this:

Event Type: Data Change/Updates Only and the condition for it to trigger is

or([Column X]="ok",[Column X]="Not Ok",[Column X]="Not Applicable") 

So once I input one of this values in the column the bot is triggered and it runs a data action that writes the current usermail and datetime to a column i made for that and it works fine the first time i use it, the problem is: once one of these values is already written in that column every other change that is made to that row makes the bot trigger again changing the useremail and datetime of the column I made to monitor changes on [Column X].

Is there a way i can make this event trigger only when the column I put in the condition(Column X) is changed ? Sort of like the changetimestamp expression works but what i really need is to keep track of which user edit that specific column.