Today on my map I have been on for like 10 months I went to a previously located and explored stronghold to insert the last of my eyes of ender to activate the portal, only to find my portal, along with the entire stronghold are gone. Not like deleted, just like it and the surrounding area have been replaced with a different biome. When I throw the eye of ender it also just leads me to solid rock, nothing else underground now. Now this is a world with a verified stronghold and all previously. What happened??
There are some world generation bugs in 1.4.5, that I have to concede. Always back up your world after every play session, you never know when things just could go wrong. You'll have to find another stronghold and hope the others are still there.
Best of luck!