Mark bug on text layer

I made a text layer and put text in it. Then I duplicated it using alt and drag to the desired timeline. 
Then my current layer that has a different text needs marking. So I used Mark tool then I noticed that it also mark the text that it came from. All the text that has been duplicated are affected by the marking bug. It copies to all the text layer.

Though its not affecting my output. I think you should fix this. 

See images attached for reference.