As title says, cap is 250 for friend entries.
I would call it a bug 
not like there is any ingame text explaining you have hit the cap… aka too many steam friends and you add their alts… just fills up… over the years.
The effect is if you ask to friend someone, and they accept. On my end I get that they cancelled it, but they get it as accepted and also get me added on their friends list. ( No entry on my side )
I cannot say i would have this problem…
Maybe if i would add all friends and theirs alts too. But i dont actually know is it account based Or name based… Dont rly remember
name based… so etc if a steam friend has their main + 9 alts… well you get 10 entries on the friends list
missing a “sort by last online” option there 
for some cleaning…
i have been at max for ages xD
i always need to remove players and its even worse while streaming and doing giveaways
people would like to add me but I always have to remove someone, even tho i have players that are not playing they are dear to me and i do not want to remove them because who knows,’’ they might come back’’ some day just get rid of that limit already 250 is such a low number when it comes to friends and their alts
woops, searched friends list before posting… but didn’t look close enough… yeah multiple of these posts with the max cap.
I wonder if this is something that could be modded? Or if that breaks the rules… WHO knows
I don’t have this problem. 
Now I feel bad for asking so many people to add me.
With us all so spread out, even on same worlds, it’s nice to see that green dot on the horizon.
Can be very lonely building on a sovereign.
I have this problem, need more space
I’m still at half that xD everyone knows everyone so I never add no one
complained about it longtime ago and they moved it from 100 to 250 our changed it two times not sure but they done it before
Got a few I’d love to unfriend.