Banners and Bannerman passive

I don't know if this is intended or not, but when running a banner with the passive bannerman to maintain the banner buff for 4 seconds after leaving it only works if you actually leave the banner. If I stay until completion, it does not give the 4 second buffer to place it again. Basically incentivizing you to wait until the last couple of seconds and running out of it. Sorry if this is intended and I wasted your time.