Interaction Between Bannerman Passive and Party Member's Banner

The passive tree node Bannerman says:
"Banner Buffs linger on you for 4 seconds after you leave the area."

I had my friend allocate this passive and we tested using my banner.
We expected that my friend would continue to receive the banner buff for 4 seconds after leaving the banner’s area — but that didn’t happen.

Is this the intended behavior, or is it a bug?

Kia ora,

I can confirm this bug, my party member has the Bannerman passive allocated, yet doesn't receive the 4s lingering buffs from my banners. Very sadge.

Can confirm, party member with "Bannerman" allocated doesn't get the linger effect from the banners I place.