Issue when trying to add same competitor twice to an Opportunity

Summary:

We have defined Line Of business(FCL) at competitor level and in many occurences one competitor is associated to multiple line of business.
And when we select the competitor at opportunity then we have made the competitor DCL dependent on the Line of Business field which is a FCL.

We are facing issue with the below scenario:
For ex: XYZ competitor is associated to abc and pqr line of business.
On opportunity when trying to add competitor we select line of business as abc and in competitor dropdown we see XYZ and select it and save it. This works fine.