Users have reported a bug in Nokia 5 that makes Dolby equalizer and Surround Sound failing to work/open when opened from an app like Google Play Music and Spotify. The good news is that HMD’s Nokia Mobile Care Team has acknowledged this issue and has clarified that they are already working to fix this issue.
An XDA Forum member has posted screenshot of his interaction with HMD’s Nokia Mobile Care Team. The team will soon release an update to fix this issue. In the meantime you are recommended to download any other third-party app from Play Store. Check some recommendations here.