Why does audition slow down when many edits?

Just some background, i've been editing/mixing/mastering for years all kinds of small or large projects. I usually use pro tools, but have been using Audition for a certain job instead. One thing thats obvious, that many others have told me about as well, is that the software slows down so much after many edits exist in the session. I'm talking about a 2 track dialouge recording thats maybe 1-2 hours long, no effects, no inserts at all starts out smooth and snappy but by about half way into the session the software slows down so much theres about a 2-4 second latency while splicing/re-aligning files. Computer is no where near its CPU/Memory capacity and shouldnt be bogged down which makes me think its Audition instead. I haven't experienced this in other software and wondering WHY this is happening and hopefully brings up a question to developers to look closer into it. 

Attached a video that shows the issue in real time. (without sound) You can see the lag at each splice and drag. The end of the clip I zoom out to show how many edits in the session. There are inserts showed on the tracks, but it happens even without them.

Thanks for reading and any tips you may have.