I had this problem as well but restarting did not help. I found this fix in a GitHub issue thread that worked for me right away. Run this in the Terminal to get Safari to re-register with LaunchServices:
/System/Library/Frameworks/CoreServices.framework/Frameworks/LaunchServices.framework/Support/lsregister -f /Applications/Safari.app
Source: https://github.com/ovity/octotree/issues/1110
More on lsregister (it's not currently documented in man): https://ss64.com/osx/lsregister.html
Topic:
Safari & Web
SubTopic:
General
Tags: