So I've been out in the garage polishing the insides of those Marco 3/4" blue, green and orange see-thru inserts... Looks like they will be fine. Like I said, it just takes more time. Patience is a virtue! I should be thankful (defects aside) that these are even available at all.
FYI, for anyone else that is having this issue, just use a Dremel cylindrical polishing tip with some Enkay blue compound. Takes a bit of time but if you rotate through all your 3/4" inserts you can avoid overheating them.
I will proceed with these old style inserts for now but if I see any other QA/QC issues, I am switching to the starburst inserts.
Edit: Shout out to Pinballife! All the inserts I got from Pinballife (clear, opaque and starburst) have no defects. The only inserts they didn't carry are the ones I am having trouble with (with the nasty swirl marks).
Thanks everyone!