Milou seems to drop affection very rapidly over time, before and after I recruited her into the rebellion and before and after it succeeded.
It's only 1 or 2 per day but it seems mostly consistent. I didn't see any traits that should cause this, so I'm not sure why it happens. Typically most of the characters will stay largely static in affection except for ones with certain traits or a bit of occasional movement from random events or other characters raising/lowering it.
Is this an undocumented feature of the character? I haven't gone through the code to check myself but didn't see anything on the wiki. Several times she's gone from soulmate or undying down to neutral affection over a span of a few weeks or a month, but other characters don't.
This was the last version - not the most recent.