Zero star boars don't drop meat 100% of the time, it's roughly 50% of the time. One and two star boars always drop meat.

No matter what star level boars always drop leather scraps and will drop trophies 15% of the time.

Deer drop meat and hide 100% of the time regardless of star level, and drop a trophy roughly 50% of the time. Neck tail drop 70% of the time from a zero star, 100% from higher. 15% drop rate on neck trophies.

This may not be a bug. It's probably just the % chance, or you're not seeing the meat if it is dropping.