Raider gaining Onslaught buff

I am playing Raider with allocated Rapid Assault ascendancy node, however periodically I see icon of Onslaught buff in buff string from allocated Graceful Assault node. Does that mean that I gain Graceful Assault Armour and Evasion during Onslaught only during obtained buff despite I always has Onslaught?

It should not, you always have Onslaught with that Ascendancy node.
Have you checked your Armour/Eva when standing still vs. when you see the icon?

I play raider with Rapid Assault too. (The passive that gives permanent onslaught)

I have boot with the mod gain onslaught on kill.

So when I kill I see the onslaught icon on the top.

It does not seem to affect my character in any way.

in the first case you get the Onslaught property from the passive skill
int the second case you are granted it by a buff, therefor the icon shoes up

the only difference is the icon