Did some digging on the repeaters, and I see a couple possibilities; I suspect the reality is a combination of more than one. My half educated guesses would be:
First, you may be hearing linked repeaters. Less likely for the GMRS side now that the rules have been clarified to disallow connections via the internet, but not impossible. More likely on the ham side; i didn't see any notes or common call signs that would solidify it digging a little on repeaterbook, but there are a few repeaters west and north with matching frequencies.
Second, an unhappy transmitter/amplifier throwing harmonics. that 446 frequency is a bit, but not horribly far off of 3x the 147 frequency.
Third, you have a repeater (or a ham) transmitting close by with a fair bit of power, and it's simply overloading the front end of your radios, so it seems to be bleeding through on other channels it isn't actually on. While it sounds like they've improved somewhat (varying between models and even examples of the same model), it's still a definite possibility. (one of my UV5R's will go completely deaf (desense) with as little as 1/2 watt in close proximity, even on a different frequency).