Should you worry? No, it's normal for many drives at many speeds.
You're using a rebadged LG drive, and LG drives are known (1) for doing drastic recalibrations due to their very...specific write strategies and (2) for sticking to these write strategies, consistently. Their newer drives seem to be a little less aggressive, but they can easily still produce rings.
On older LG drives, these recalibrations occurred every 2x or so, so on a 16x burn, hitting 8x - 10x - 12x - 14x each resulted in a chance for a new ring.
It might be similar here, though the newer LG drives (like the one your drive might be based on) do recalibration checks more often; you could see one ring until the drive reaches 8x, then another ring for the remainder of the burn at 8x, and there might be more smaller rings if the drive decides to readjust itself.
Every little dip on this graph is the drive making a decision, and is a chance for a new ring:
(your drive may be based on an NS95 instead of NSB0, but the graph would be similar)
Even with this, assuming the drive makes a good decision & assuming the media is OK, write quality is fine.
On mediocre or bad media (or media with very bad firmware support, or with a bad drive), the drive might have a greater chance to make rings because it has to figure out the best way to compensate for a problem it encounters. It might decide to make drastic changes at every single checkpoint (trying feebly to improve quality), rather than only once or twice.
Different disc models will respond differently to the drive's changes, and the drive will decide differently depending on the disc model. So yes, it is normal for two different models of disc to have different ring patterns.
(Note that different brands may use the same disc model, with the same OR different quality, and discs vary in quality anyway).