It's difficult to tell if the sound is abnormal, because we don't know what it sounded like before. I hear the tell-tale whine of a VFD carrier frequency (the rate at which the tiny little DC pulses fire), but if this is above and beyond that, you may have EDM damage to your bearings because of the VFD output and poor grounding. EDM damage is the result of a voltage build-up between the stator and rotor as a result of the high frequency pulses from the VFD causing what's called "common mode" electrical noise, meaning it is referenced to ground (earth). CM noise always wants to return to its source, in this case the VFD, so it looks for a path through ground. If none exists, the voltage builds up a charge on the rotor and it eventually exceeds the dielectric (insulating) strength of the grease, then discharges across the bearings to the frame to ground. As it does so, it causes microscopic "pits" of voltage damage that is essentially the same as Electrical Discharge Machining (hence the name) such as a welder or plasma cutter. Once a pit is made, it is easier to find the next go around and the process escalates to destruction.
Here are some images from someone else in this forum as to what this looks like.
The solution is to use a "shaft grounding ring" on any motor run from a VFD, or the next time you replace the bearings, replace the seal with one that includes a shaft grounding system. Inpro/Seal offers them as do others. (I don't work for any of them them.) Another alternative is totally isolated (ceramic) bearing assemblies that don't actually stop the voltage built-up, but it stops the bearing damage.
If this noise has always been like that, it's just what I mentioned earlier, a whine that is the side effect of being run from a VFD. The high speed pulses that comprise the pseudo-sine wave output has a magnetostrictive effect on the steel laminations in the motor core. You can increase the carrier frequency rate in the VFD output via programming, but there is no "free lunch" in that increasing the rate will make the motor appear quieter (it actually just moves the sound above human hearing), but causes more heating inside of the VFD, so you have to de-rate the VFD. If you have no head room in the VFD size, you can't do it.