It's not so much that callandor had that ability, though TP mechanics seem a bit weird and it would have been nice to have gotten some sort of brief blurb about why/how Callandor had this function. More it is that Rand's final attack confirmed that he really has fought the DO countless times and repaired the bore. Had he killed the DO and had him replaced with Fain or one of the other variants we've all kicked around then it would make sense that the DO didn't see it coming. This method not only required the DO to know how the bore was resealed but requires his own power. Now granted that the turnings aren't supposed to be identical but Rand would still need each repair variation to involve his using all 3 powers. Meaning the DO would have to be worried about Rand getting TP access in some fashion and have previous variations of this occurring to do some educated guessing of how it occurs.

It wouldn't have to go down exactly like that, in theory Rand could have accepted Lanfear's aid way back or maybe post-tFoH shown up with Nyneave, Callandor, and a leashed Moghedien or a Forsaken who got compelled as apparently happened to Graendal at the end there. It might not even need a TP angreal for the job, just access to it, but Callandor might be a totally different object next time around, like an axe, or staff, or ornamental statue. For it to make sense the DO has to have some reason why he lets the TP be used by anyone at all. We can speculate the low access to it is either from his understandable concerns about giving it to a lot of people rather than an elite semi-trustworthy core or a limited supply, or both, but it wasn't really established why anyone would need access to it. Without a reason why he has to hand that double-edged sword out it doesn't really make sense for him to do it at all, or why he wouldn't issue some kind of warning, even if it were BS, designed to minimize the risk of something akin to what happened.

As is, it is sort of like a werewolf handing out silver bullets to his human followers even though everyone they'll be fighting would go down from a normal one.