Hi tgg1304,
Sorry for the late reply.
I have never heard that PG or VG burn at different rates, but they do flow at different rates; VG being thicker.
Since PG flows better than VG, it's possible it would move through the wick slightly faster to give a different vape experience.
If you chain vape or puff hard, high VG liquids can have a hard time keeping up, sometimes resulting in dry hits.
I'm just throwing out some ideas for you to think about and perhaps they will make
sense in your particular situation.
Good luck.