Duplicating a Caption slows down Premiere pro after several iterations

If you have a caption graphic, and you duplicate it (using the alt + click to drag), or simply slice of a bit, to create a new one, and you do this several times (perhaps 5+ times), Premiere pro starts to lag considerably.

The only way to overcome this, is to create new caption every time, instead of simply duplicating.

I'm guessing some kind of memory cache is being flooded with previous + new data, multiplied by every time you duplicate the caption.

Please fix. thank you.