I replaced single-speed pool pump with 3-phase and VFD years ago. I also had SMA SWR2500U grid-tie PV inverters.
With both connected to the bottomless grid, never had a problem.
After I installed Sunny Island, I replaced the GT PV inverters with (transformerless) SB 10000TL-US, because it would respond to frequency shift. When it tried to reconnect to island grid (generated by SI) while VFD was operating, it reported an internal error. Probably looking at voltages on its input and couldn't make sense of them.
Because Sunny Island was not bothered by the load, I thought transformer filtered higher frequencies. I replaced the Sunny Boys with 5000US. But those threw a similar error. Something about relay failure if I remember correctly.
I'm afraid of letting them experience repeated errors, something about getting a permanent error flag set.
I think the issue only occurred when VFD was already operating at the time GT PV inverter was powered up and tried to connect to AC. It may not be a problem if VFD is not turned on (or loaded) until GT PV is already operating.
Possibly some sort of choke ("reactor") on AC input would help. I have one on output to protect motor. A single winding choke big enough to do anything at these currents and frequencies would be huge. A "reactor" or common-mode choke of course is great at blocking common-mode, but would probably pass most differential mode moderately high frequencies.
I've bought some Lambda power-factor correction modules (PF > 0.95, 120 to 240Vrms in, 360VDC 1kW out). I haven't tried them yet because they require additional support circuitry.
I've looked at AC current powering VFD. Flat line with little peaks of a sine wave, when AC voltage exceeds capacitor voltage. I tried spinning an induction motor on the AC line at the same time, thinking it would smooth out current draw, but waveform looked the same.
There are some VFD, I think the reversible ones (able to return power to the grid, e.g. as the elevator is going back down) which may not use bulk capacitors, instead chop waveform from 3 phases in to 3 phases out. Those may synthesize sine-wave current draw, needing only a bit of HF filtering. Others use PWM boost converter to synthesize sine-wave current draw (like the Lambda modules I got).