"Target is out of range"

This message pops up on anything within 5m that happens to be moving away from you, and results in the ability not being cast regardless of the skill being 'lit up' on the skill bar (which only occurs when something is... you guessed it: in range). This leads to many kills not being secured in fast-paced content. Speed has always been an issue on melee magblade; this just perpetuates the issue.

Theories on the issue:
-Objects directly on the 5m threshold are being considered Out of Range.
-The trigger to activate the use of this ability when something moves within range differs from the prerequisite distance needed to actually cast the ability.
-There might be a hidden cast-time attached to this ability.
-Latency; which means it won't be fixed until there is a server overhaul.

I'm fairly certain I recall Uppercut/Wrecking Blow receiving a range increase due to this specific issue, albeit there is a cast time attached to these abilities (even though in the right hands it still weaves just as fast, if not faster than instant cast spammables, but whatever, I'm derailing my own post).

Does anyone else experience this with instant cast melee range abilities? If so, which ones, and have you found any solutions?

Edit: Light attacks from a 2H weapon will land on a player moving away from you, but still reads "Target is out of range" when attempting to use concealed weapon on that same player. This leads me to believe there is an actual mechanic busted here.