I see this occasionally. It's not specific to 0.3.3.x. I reported it back in October 2017:
https://lists.torproject.org/pipermail/tor-relays/2017-October/013328.html
Roger replied here:
https://lists.torproject.org/pipermail/tor-relays/2017-October/013334.html
MaxMemInQueues is set to 1.5 GB by default, which is why the problematic circuit uses that much RAM before its killed. You can lower MaxMemInQueues in torrc, however that will obviously have other impacts on your relay. If you have plenty of RAM, I'd maybe just leave things alone for now since Tor is already killing the circuit.
I agree in theory some mitigation against this would be nice, but I'm not smart enough to offer anything specific. It seems Roger and other devs are already thinking about the issue.