Error while finalizing DVD-R. Media issue or burner problem?

I use a Liteon 411 with FSOF firmware, and have been using Ritek G04 successfully, without a single coaster, for the last 150-200 or so burns. A new shipment of cheaper RitekG04s arrived, but 5 out of 5 tries I got an error message during the finalizing part of the burn, and ended up with coasters! I did some “test burns” first (the part where they only test and not record) and that worked ok, but the actual burn always screwed up during the finalizing part. I was afraid my burner was malfunctioning, so I borrowed some older-batch Riteks from my friend, and those worked. Then I went back to my new Riteks, and same thing happened. I know it sounds like a media issue, but is there even a slight chance that my burner is causing the problem? The new Riteks I bought were all silver-matte top, without the Ridata logo in the middle, and has a “H5…” code in the middle clear plastic ring, and came in non-labeled light grey cake boxes of 25. I got 100 of them, so I’m not terribly happy right now.

Again, the problem only happens during finalizing… is it possible that media is causing this?

First scan your burned disk with cdspeed or dvdinfo to see where the errors begin to show.
Then, just put a limit to the contents you want to burn on those disk? For example don’t exceed 3.8-4 Gb.
Unless you bought with a 2 (replacement disks) for 1 (coaster) warranty like with

This sometimes happens with a bad batch of disks. This happened to me with a spindle of printable Ritek G04.