I'm not sure if this is a new bug or something else.

Preston Garvey just keep repeating the max level affinity conversation with me(the one you get his perk and romance) even if I've already spoken this countless times. He also seems to stop having settlement radiant quests conversation although I'm still receiving the quests from him.

I did some searching but still can't find any solution, is there anyway to fix this?

PS: I play female character but didn't romance with him.

First question is, what mods are you running? Second is, did you remove any mods from your game? Both can cause problems like this.

1. I only have 2 small mods of cloth/armor, nothing relates to any game mechanisms.

2. I didn't remove any mods yet since I only have 2 small cloth mods, but I think I'll give a try.

Thanks for the help.

There are some glitches in the Bugs section

http://fallout.wikia.com/wiki/Preston_Garvey

If you don't "romance" companions, but keep them as best friends - max friendship, now and then they want you romance them. They will repeat it because their heart tells that "you" are the choosen one

Cheers,

-klevs