I remember it happened sometime ago with certain keyword, but since DDG simply use Bing search result, the real problem lies within Bing.
Use DDG and try to search for "bitcoin wallet", let me know what the first result is..
I get the following results :
https://bitcoinwallet.com
https://bitcoin.org/en/choose-your-wallet
https://cryptowallet.com/best-bitcoin-btc-wallets/
I also got same result using Tor Browser.