What should I have learned from your link to Updateless Decision Theory that causes me to suspect that EU maximizing with Bayesian updating on a universal prior is wrong?
From what I can glean from the UDT descriptions it seems that UDT defines 'updating' to include things that I would prefer to describe as 'naive updating', 'updating wrong' or 'updating the wrong thing'.
Upvoted entire ancestor tree, for similar reasons.