"CoinBase" was the unreliable Data Source Provider.
I switch to Bitfinex and the problem was solved.
You have many options in the drop-down list for Fiat Source and if you have problem if fiat value display with one source, switch to another or other sources, before your problem is solved.
BitFinex
BitPay
BitStamp
BitcoinAverage
BitcoinVenezuela
BlockchainInfo
CoinCap
Coindesk
CoinGecko
Coinbase
Kraken
Yadio