Is this a know bug or something?
Yes that happens to me at most settlements after an attack.
Leaving for a while and returning later or sleeping for a few hours allows trading again.
That happens to me all the time. I just go do something else away from that settlement for a while until they go back to normal.
After an attack on any of my settlements I always want to upgrade all the settlers gear with what I stripped off of the baddies. The settlers cant stop thanking me to get new gear though and I have to leave and come back later to help them out....idiots.
Happens to mee too, quite often. Currently at lvl.107 and save file reads a little over 26 days. It feels like it's getting buggier the more i play. Save file size is currently 21,50Mt. Also the money invested in shops seems to have bugged out for me at least.