I had the same trouble and it was fixed by changing bottles, too. I am wondering if it's the amount of pressure used in squonking that may be torquing the bottle out of alignment while it is threaded. Then, once distorted, it doesn't go back so it starts leaking. Not sure, just my hypothesis. I put a tiny square of the receiving end of some velcro tape behind the bottle (on the post that separates it from the battery) to minimize the amount of distortion created on the bottle. So far no more leaks. Just a thought.
Cnew, perfect! That is precisely what I was going to suggest. Lucid, in addition, you may want to put an O ring on the neck of the bottle to prevent over-tightening. Lastly, I did have occasions where an air bubble would form right at the opening of the bottle. Check for that, too. Let us know when you get and try out your new bottles.
fourth! WHAT a BUMMER!!!