melee weapon 'Sigma and Octanis', not able to execute a heavy attack.

[hailas]

As it sounds really, as I press Mouse 3 the sword and shield weapon 'Sigma and Octanis' no longer executes a heavy attack. This is while I have it equipped. 

[Periareion]

Something is seriously wrong with Sigma & Octantis since the last 1 or 2 patches.

Best I can tell it adds an extra attack at the start of every combo. For the stance Eleventh Storm it's a shield bump. For the stance Final Harbinger it's a cross slash. Which appear to be the default attacks if you stand still for both.

This completely breaks the flow of combat and mobility, especially on a slide attack. It also causes weird issues with jump slam attacks where the frame hovers above the ground for a bit before hitting the ground. If you do a jump slam attack over a long enough distance it throws the shield AND does a ground slam. Heavy attacks on the ground don't work at all but you can still do a heavy ground slam attacks while in the air.

[Pulsar63]

The same happens to me with the Orvius glaive: heavy attack button (mine is set to Canc) does nothing.

Some days ago it worked fine; so I think the latest update messed up some melee weapons womehow.

[kwlingo]

Im assuming all throw melees have the new glaive update with heavy attacks.