First, if you activate it then quickly un-equip and re-equip the sprite, the shield stays. Even though it's not functional, doing it over and over leads to some pretty funny results.
Second, I'm guessing this is a bug, but teammates can damage it, making it almost impossible to use around people. Me and a friend tried it out, swinging at it with a rocket hammer made it go wobbly and a 5* brandish charge outright broke it. Bombs like dark retribution affected it too, but guns seemed to not do anything except for the birds from sentenza/argent peacemaker charges.
And lastly, my friends have told me several times that they sometimes still see the aura after it's already worn off, but I can't see it and as with the first bug it's not functional.
I can additionally report that the last improvement which is supposed to increase duration and something else does not increase duration. I tested it with a guildmate who had maxed it, but our durations were the same. Already reported this through the in-game bug report system, though. Hopefully we shall see fixes approaching us soon.