When viewing the block data with 'F3' the hopper flag:enabled does not change on disabling or enabling the hopper. If the hopper is enabled on joining the flag is enabled:true. On powering (disabling) the hopper the flag is still enabled:true. On rejoining the flag is enabled:false. On enabling the hopper again, the flag still shows enabled:false.
The hoppers still work correctly, its only a GUI error, which is still confusing when controlling things