BioShock 2 natural camouflage glitch

I've been light on the blogging at the moment, I will get onto to tertiles and deciles at some point. I've just been busy playing through BioShock 2 on hard; using my knowledge to eke out the few resources and balance tonics and plasmids for the fight.

I've just reached Fontaine Futuristics and have been tasked with destroying the security relays. One down I head to another area and demonstrate my Plasmids; save after the battle; and head off only to discover my Natural Camouflage tonic has ceased to work.

This may be the most useful tonic in the game; and to be honest at times I consider it a game-breaker (as I did in BioShock1 in which it also appeared). Essentially when you stand still and do nothing you're rendered invisible. If an enemy bumps into you it's cancelled; if an enemy spots you then it won't activate until their hostility level drops normally through their death.

What makes this so useful is that although you can't use weapons or plasmids, you can still use first-aid kits, EVE hypos and hack machinery within range. This latter ability is the most useful as hacking gone wrong summons security bots that can't see you even if they bump into you. Best of all as they bump along you can hack them without being seen and get yourself a couple of bodyguards for free.

But now it's not working. The tech guys at 2K know about this problem which seems to affect all platforms and across various levels. My bet is that you've been tagged as being in-sight of a hostile and it hasn't untagged you when they die. As you can't kill them again this state persists for the rest of the entire level unless you can reload to a previous save... which would be my initial AutoSave; damn.

In the previous game this would have been resolved simply by moving from one area to another via Load Screen; but the sequel runs on the old mantra of one area per level; you can't go back and you can't go forward without completing the level.

A patch would be really nice.