YEAH i was about to write that, because he remembers everything but acts like he forgot what she have done or forgave her, so think the sword must have heard her and her thoughts and regrets about killing him
I am pretty sure Lan Ghiosa does not really understand feelings or nuance. I think it is a 'divine' sword that 'hates evil' just in name, like a computer program would. Plus, i am sure the Ghiosas are more than what was said. They are part of something bigger, a scheme behind everything. As such, i expect all Ghiosas to be tools serving one entity. You would have to feed their "AIs" continually with food for thought and various experiences in order for them to learn and develop into a proper sentient entity. Which i am sure Echi does, but not really Yurien.
In this sense, i also expect that Bardere Ghiosa is not a cursed sword at core. Either it was deliberately corrupted by humans and lost its true form, or it was created like this until it finds a master capable of revealing its true form. Which would explain why Bardere Ghiosa seems to teach all his masters about the way to rewind time and cancel what was done once it awakens. And why Kairos Ghiosa just sits there waiting, and only asks what the owner would do after time is rewinded. All in order to find and develop the ideal master, all the while cleaning the slate once the deed is done. All a long, nightmarish trial made to forge a true master for the true sword. I wouldn't even be surprised if the price at the end of the road was godhood. Bardere Ghiosa's previous master may have failed ultimately, when he renounced his ideals for fear of the consequences. Theories theories.
All this feels so much more appealing to me than the pointless so-called romance.