Yeelight Bulb lamp responding unexpectedly

10 days ago I bought two Yeelight Color S1 bulb lamps and yesterday one of them started presenting an odd behavior. It shows colors that were not programmed to and brightness is changing differently than I set on the iPhone app.

I have started resetting it and adding it again to the room. It worked for 24h, but now it has started to behave incorrectly again.

Can someone help me, please? Thank you.