Microsoft Dynamics CRM Option Set Value Suddenly Auto Added

Hi, Option Set Value can be added through Your field customization and you just add the item value, like this and commonly, it will be done by CRM Administrator only since it is related to Field Structures.

But, have you ever faced condition that your Option Set Value suddenly become added and added without anyone changes, you realized it when you see the data, the Option Set that it used to be only has three values : High, Medium, Low, but currently it has 4 values, that is + Lowy, and you checked to your System Admin or System Customizer are they have added some value, then they said they have not done any changes.

Is weird right?
So this is maybe the scenario that you could face, and I share to you because one of my customer ever reported that to me, and I was very confused at the very first.

First, you have done the customization and currently you have 1 local/non-global option set field called as Local Rate, with 3 values :
1. High
2. Medium
3. Rate

As this :

You are very sure that you have created that field and only 3 values.

Then, your client/user does the Import Data as usual, it has been repeated several times without any one realizing any product, so still safe.

Then, your customer still does the same import data for example, here is the data

Then, import using standard CRM improt wizard and suddenly, they call you and ask whether you have added some Option Set Value, because when they export back the data, they checked that they are 4 values, instead 3 values, the CRM Administrator also feel that he did not add any value. So, I was confused at the time, because after already handover, I have never been handling that anymore.

Then, I check to their database, and yes, right, the data like that :

Then, I check to export, and it shows as well :

Ya, then I check to system customization :
Yes, then, I found that there is "Lowy" as new value added..

Yes, then I try to ask customer about the data import, then I try to re-import to learn about this case.

Then, I learn that in one of the data record, they have "Lowy"

Then, I go through to repeat again my step using that data, and I checked to Data map during import, and here is the cause :

We go to Local Rate field and click the lookup button
then will open a small pop up Option Set Mapping :

So, here is the summary how to solve this case :

SOLUTION :
1. If you don't want to add new value, please check again your data (this is quite difficult)
2. Go to Option Set mapping when you do the data import (DON'T JUST CLICK NEXT until finished :) )
3. Use GLOBAL OPTION SET

Hope it helps!