There is another person having this problem. http://support.advancedcustomfields.com/forums/topic/taxonomy-issues-in-version-4-4-1/#post-25862
ACF 4.4.1 changed the taxonomy field to be ready for the WP 4.2 update
4.4.1
Taxonomy field: Added compatibility for upcoming 'term splitting' in WP 4.2
Taxonomy field: Major improvement to save/load setting allowing for different values on multiple sub fields
Core: Minor fixes and improvements