Yes it has been frustrating. What is the point of checking the boxes "save my profile" or "apply the passport details in the same booking"?

I agree that it is a hit or miss (perhaps miss 80 % of the time). Sometimes I did not need to enter any details in the passport to finish the OLCI, but in most of the time, I need to fill in some details, be it the expire date only or all the details of my passport.

I thought it may have to do with the departure/arrival point, but I could see any pattern so far.