Maybe a small test would be in order.
Get a torque wrench and set it about five pounds short of the installed torque. Check the bolts in the assigned pattern. Also, check to make sure all of the hardened washers are in place under the nuts holding the head down.
For that matter, you may want to pull out a stud and make sure the threads are at least half covered with thread sealer. It isn't for the heads, it is for the block.
Maybe see if you can turn the freeze plug in a hair. For that matter, drain the block and pull out the plug, put some ARP thread sealer on the threads and put it back in the block. While it is out, check to make sure there isn't any cracks around the freeze plug hole.
Hope this helps. Coolant leaks can be annoying.
