Ran across this issue this morning. I defeated all three Daughters of Lerion and received their sword keys in my inventory. I then went on to the statue of Lerion where you're supposed to insert the three swords to open up the secret passage. I was able to insert two, but when trying the third Eivor says something like 'I do not have this key yet'. I double checked my inventory and it's there -in this case it is Regan's key- but no matter what I do the game doesn't recognize I have it. I reloaded the game just in case, but that didn't fix it. Anyone have this same issue or know of a fix? Thanks.