Automation chest and aging barrels?

[vivid tartan]

Having set up some kegs and chests for production I than wanted to expand with some Aging barrels.
But when I put the aging barrels at max (8 per chest) it seems that it glitches somewhat as not all the barrels are filled with wine, and it seems random as to wich barrels get filled. Anyone who has done this and now if there are limits that apply to this?