NEO 2T Issues with cassette alignment and low pitched rumble/grinding in high gears

Just got mine today. Same thing. Is this just a characteristic of the electromagnets at low RPM / high resistance?  It sure feels like a grinding vibration to me, just not right...

Typically the grinding sound is related to metal dust coming between the magnets and the coils. The metal dust is often first introduced when the lock ring is tightened. The lock ring is rather soft metal and will release some very fine metal shards that end up being attracted by the magnets and end up causing the grinding effect. You can clear these by requesting Garmin to send the extractor tool. When you report the grinding problem they will send you the tool for free. 

I did have success contacting Garmin via phone. 

Outstanding design.

I actually had contact with Garmin over this at the time and it won't fix the problem. Debris inside the device makes a metallic grinding noise that can be fixed this way, but a lower pitched rumble felt through the pedals is in fact a different issue.

The rumble is indeed a different problem. You can solve this by lowering the intensity in Zwift (see my solution posting in this thread).

Not using zwift. Could consistely feel rumble at 90+ rpm in harder gears. If you're happy only using it to spin at tempo this trainer is the one, but for the money it's a poor piece of kit.

Brand new unit here and experiencing the same issue.

As this is my first experience using a trainer, I wasn't sure if this is expected behavior or not. I bought the NEO 2T due to living in an apartment and the stated noise levels being low, but the vibrations caused by this issue are fairly significant and I'm worried I'm going to get complaints from downstairs.

It almost feels like Road Feel is turned on and it's simulating gravel at a very low level (just to be clear Road Feel is disabled).

This happens at any point I increase power, the harder the effort the louder and more vibrations I feel and hear through the pedals.

Disappointed given the cost of the unit, and being in Japan seems to have limited support.

I have the exact same issue with my Neo 2T. I remedy it in Zwift by setting the Trainer Difficulty to 30 per cent. This remotes the rumble. 

I have the same exact issue.   New trainer, Only been using the trainer for 3 months.  Took video and tried all the suggestions Garmin support asked for and still gave the issue.  Waiting for a response.