I don't this will happen because having a soulmate is a blessing from the love god, I don't think he'd appreciate throwing a monkey wrench in an already good relationship.
The reason why Rentarou doesn't cross the line is because if he did the manga would get pulled by the big cheese, but in doujin land there is no such restrictions
Basically, more buzzwords lead to more traction in algorithms and people. Same goes for the protag being genderbent even though it has literally no impact on the story.
Big personal pet peeve of mine is whenever a manga draws someone "without" makeup and it's literally just the same drawing. Just don't draw attention to it if you aren't gonna go the extra mile to actually draw it
So I think this more or less establishes that MC's soul is something that is affected between loops, probably due to the trauma deeply etched into him from each run.
I like to imagine it's not a glitch, but something similar to how in BoTW the old man in the great plateau exists in multiple locations at the same time, because that's more seamless than teleporting him around.