Blockfolio has problems keeping up with demand. Their servers can't keep up with all the queries from new users, so the prices are often wrong across the board. Delta is better, and they consistently have the correct prices for the top coins like BTC, ETH and DASH. But any smaller cap coins seem prone to the same data lag problems that Blockfolio has.
One more note on Blockfolio: they have really bad data retention/privacy policies. There's no great portfolio watching tool at the moment. Delta is as good as it gets right now.
One useful tool: Tradingview added dollar-calculated values for altcoin markets, based on BTC price. You can only view one chart at a time (or up to 8 at a time if you have a PRO account), so it's not like Blockfolio. But it's useful. https://www.tradingview.com/symbols/DOGEUSD/