Just checked last AFS4 update and seems like the issue with INTC legs is finally fixed!
At least all approaches that couldn't be completed in my above post (D23 MMMM, D26 MMMZ and D36 MMVR) now can be flown and finished.
Thank you for solving this, took some time but looks like LNAV now works as it should
I was a bit disappointed at first but now that it's fixed I have the motivation to go back to airport creation tool and continue working hard