I was mining something near one of those thunder bird owls and at the exact moment my pickax hit the stone, some lightning struck (it might have struck me, but I can't remember). Since then, any sound for a basic action like mining or cutting a tree is nonexistent. The music or clicking around the build menu is normal volume though.
Steps to Reproduce
get hit by lightning while hacking away at something
This issue has not been confirmed by a developer yet.