Disregard the "how do I fix?" part of the prior thread on the pacman trust db getting corrupted. (I got it fixed)
Backtracking, the problem occurred after an attempted update when there was a temporary failure in name-resolution due to the DNS server undergoing a reboot when the pacman update was attempted.
Corruption of the trust store should not occur due to name resolution failure. Is this a "feature" of the latest pacman release? Does it need further investigation?