Given that
Shiraiken hasn't answered my question yet
maybe he hasn't had the chance to play the new version yet.
I had to test Kate's story myself, the pregnant Kate thing... I had to summon all my strength for fear of the bug
But first I wanted to be sure... that the bug was due to the save file, since he himself said that his save was from version 0.6.0.1. While my save was from 0.6.0.0c. I thought that maybe my save could be free of problems.
So I tried to get Kate pregnant in version 0.6.0.0d. And... it didn't end well

The problem was not the save file. But the version of the game itself. Unfortunately I think that at some point something got bugged in the previous versions of the game, causing the game to bug if set to NTR Off. Because just like
Shiraiken, it gave me exactly the same bug.
That is, Kate who doesn't know if the child is the MC's son or someone else's. Strange thing, since like him, i set the game to NTR Off. And Kate was only with the MC. Never fuck other men.
This threw me a bit, but after reading Chyos' comment about the bug... I started to think that, as I was saying, the error occurred many versions of the game back. Since in Chyos' message, he almost confirms that someone else had already warned him about this error. But that he hadn't understood what it depended on and then... he forgot to fix it. And that in the next version, he would have fixed the error, since this time he had found the bug and understood how to fix it.
So thanks to
Overlord070 who alerted Chyos about this bug. I tried the new version. Since as I said, v0.6.0.0d was also bugged. I had no choice but to move all me save file to version v0.6.0.5d. And hope that Chyos had actually fixed the error already there. Because I thought he would have fixed the error in version 0.6.1.0. Since in the changlog section, I didn't see anything about Kate. If I were Chyos, I would have also put that fix in the changlog list.
Anyway, I don't know if I was lucky or not.
But I tried to load the save in the new version 0.6.0.5d and tried to load the sequence where Kate goes up to the room for the first time pregnant, with a big belly. And I tested the situation again. And
thank God, this time no bugs. Kate behaves normally. No wrong dialogue. I just hope it wasn't just a coincidence. Because to test this out, I simply got Kate pregnant and let a bunch of days pass in the game without playing. So now I have to reload the save before the testing.
Anyway as I said, it seems that the bug has been fixed. So whoever ran into that problem, can try like me to switch to the new version. Because it seems clean from this bug.
Again Thank you
Overlord070 for warning him about the bug.
I hope it wasn't just a coincidence, because now I've finally moved to version 0.6.0.5d
