This follows on to "Security Prices - Issue with yesterday's closing prices changing to today's price for all holdings" (https://community.quicken.com/discussion/7939889/security-prices-issue-with-yesterdays-closing-prices-changing-to-todays-price-for-all-holdings/p5) which was closed with dozens of replications, calls to Quicken, tech support filings—and no solution over the years.
To show how replicable the problem is, here is my Quicken price history for ticker BSV, showing the onset of the wrong pricing at the start of the year, and the periodic nature, where the correct pricing, around $77, appears during the business day, and bogus values appear irregularly when updating on evenings and weekends.
Since this particular ETF changes little in share value, I'll just pin the price and remove the ticker symbol, as a workaround.
Hoping this is of value to others having the problem, since afaict there is no resolution in prospect and no point in creating Yet Another documentation of this with Quicken.