If this is the cause (which must for the moment be considered unproven), the way to combat is probably not to alter behavior of real nodes, but rather to do something like make a dummy node set to minimum power with a resistor in place of an antenna which periodically sends a packet that is valid LoRa, but invalid LoRaWAN and so will be passed by the gateway but quickly ignored by the backend servers. Though first start with an actual node with those power reducing measures, and verify if it improves performance of the other nodes. The point is that if you need something to work around a bug and keep the gateway connected, you only need one such thing, you shouldn’t need to have all your nodes chattering away at a high rate consuming battery and bandwidth.
Of course the only real solution is for the firmware source of the TTIG to be released so that the community can fix it. The fact that this did not happen at the time of product release is grotesquely in conflict with everything TTN would appear to stand for. That’s an issue regardless if gateway bugs are to blame for this particular situation, or not.
That’s somewhat dubious, this would simply not work in a network with a 1-second RX1, so if it is happening, it is probably unforeseen behavior of components used rather than an intentional feature.