Blue glow when off

I have just got 4 new mini day to dusk bulbs. One of them stays a very dim blue even when turned off in the app. I have looked on internet for a fix but no one seems to know.
Is this a software issue or a faulty bulb?

All of my A19s glow dim white when turned off. This has been occurring for years. I have the latest firmware and everything. not sure if this is something that will be fixed or not. I’m over 35 bulbs in.