I've logged about a zillion hours in Borderlands, none of it as Lilith. But apparently her phase strike "now works as intended" thanks to patches for the PS3 and 360 versions that rolled out today.
Here are the PS3 fixes, from the Gearbox official forums (fora?)
• Load times have been improved
• Lilith's Phase Strike ability now works as intended
• The introductory quests with CL4P-TP should now always progress properly
• Fixed a bug that caused the digger elevator to be unusable after completing the Find Tannis mission
• Weapon mapping to the D-pad should no longer reverse left and right
• Fixed a crash when ejecting the disc during the autosave warning splash screen
• Players in a lobby should no longer experience long loading when starting a game after one player leaves
• A bug which caused players and other things in the world to appear incorrectly on clients in networked games has been fixed
• Fixed a bug in which players gibbed in arena combat disappeared
• Changed how space required for saves is calculated
• Fixed a bug which caused the dollars counter to spin continuously
• Various localization and other text and tooltip corrections
And on the Xbox 360, tell 'em what they've won, Don Pardo:
• Fixed a bug which caused players and other things in the world to appear incorrectly on clients in networked games
• Fixed a bug in which players gibbed in arena combat disappeared
• Fixed a bug which caused the dollars counter to spin continuously
• Fixed a bug that caused the digger elevator to be unusable after completing the Find Tannis mission
• Weapon mapping to the D-pad should no longer reverse left and right
• Various localization and other text and tooltip corrections
• The introductory quests with CL4P-TP should now always progress properly all the time
• Lilith's Phase Strike ability now works as intended
• Load times have been improved
360 Patch 10/30 and PS3 Patch, 10/30 [Gearbox forums, via VG247]