Horrible bug where I can’t use a soldier, what is the cause and is there a work around

xcom-enemy-unknown

So I'll be playing my missions as normal and seemingly at random my sniper will lose all abilities except for grapple and hunker down.
When I click on those abilities get the "unh-unh" sound and I can't actually use them either.
He has his sniper rifle out but there isn't a currently selected gun (indicated by the white box in the bottom right corner)
When I click on one of his weapons he puts his sniper rifle away and then pulls it out again.
He is completely useless for fighting aliens as he can only move around and I can't even put him in overwatch.

This especially brutal because he is at the top ranking and I need him to clear out the super tough enemies with his double tap.

What causes this and how can I avoid/fix it?

Best Answer

This exact bug occurred for me last night (also on my sniper).

I dont know what caused it - but to fix it all I did was 'save', completely exit xcom, then restart - and it was fixed.