I noticed the Jagged Pike doesn’t get 2 tiles range at night, could be a problem with vision range as the guy was wearing a Full Helmet with -3 vison, It probably counted as “couldn’t see” even though other squadmembers had eyes on the target. Hitting a target 1 tile away works just fine. Will test it with a Billhook tomorrow.
The minimum vision range is 1, thus if your battle brother has -6 vision and base of 7 vision his vision is 1 (which by the way can’t be ever lowered than that). It’s not a bug, it’s working as intended – he can’t see enemies 2 tiles away from him, so effectively other battle brothers can’t “help him out” to spot the target.