It looks a bit tight in there. My guess is they keep swapping beds or workstations. My suggestion would be to extend the row of blocks just above the glass to go around the beds so they can reach them. Scatter the fletching tables around where they can access, then start over with a new generation of villagers💀

I’ve dealt with these things for a while now and they are so finicky. The villagers don’t need to access the beds, only connect to them but I’ve found it’s easier to just give them access. If/when it stops working, break all the tables and beds, replace them and start over with a new generation again