The VPN issue has been around for quite some time. I even have it at times when not using VPN, which is a complete pain! At least then, or when logged in (when they even know who it is, so not the competition’s bot; and don’t forget they are still trying to maximize pricing based on point of sale and/or your search pattern) they should get it right! LX IT’s response a few months back was that they were working on improving their detection tool. It does seem to have improved with me a bit, though. Incidentally, have experienced this with others as well, e.g., SQ, though nowhere as annoying as with LX.

I have also experienced the one day off in API, but that only seemed to be an IT bug.

As to availability when you increase pax, apart from dynamic availability, don’t forget it will take the highest fare applicable to one pax for everybody on the same booking (e.g.,, if you are booking 9 pax and there are only 8 seats available at a lower fare available in the cabin, but 9 at the higher, it will tske the higher fare for all 9), so at times you need to split the request/booking to avoid that.