Unfortunately this is another bug introduced in the 0019.5 patch. The workaround is to spawn info portion podval_sarkofag_nayti, which starts the task to find Lightning. The task description includes a photo of her location. When I got there, she appeared and I was able to talk to her and continue playing. (NB: doing this you will miss several SMS messages and a confrontation with Associate, but they aren't vital. You can read them in the walkthrough.)
Note: The teleport blocker will probably still be blocking the way to the O-Consciousness area, so you may need your jumping skills again. Alternatively you could use ESC+F2 to npp2control, which drops you outside the O-C room. There may be enemies waiting for you there, so be prepared - or turn on God mode temporarily.