Intermittent black screen with dots

[Enma]

I got this cellphone new yesterday, is currently updated with the last firmware and related, yesterday at night the cellphone started having this issue where I couldn't see the lock screen just black with some color dots but if I slip my finger I can hear how it unlocks, I have to press the button a few times before showing the actual unlock screen.
Is it something I have to send it to get repaired/ask for warranty or I can solve it by rolling back the updates?

 

[gpobernardo]

Welcome to Windows Central.

Is it possible that what you're seeing is the Glance Screen feature of the phone? Check your phone settings and see if it is activated. If it is, then what you're seeing is normal. Disable it if it starts to bother you.

The Glance screen displays a low-quality image or text (usually the clock) as a way to quickly check some of the status notifications from your phone without having to press or tap anything.

 

[Enma]

I don't have that feature enabled, actually, by enabling Glance screen now it's less likely to see that weird bug in the screen (I have seen that this issue happens when the screen has been off for a while) but the issue it's still there anyway.

 

[gpobernardo]

Hmm, now that you mention that, I think I experienced the same issue (but only once or twice) with an L535 I used to own. It happened to rarely that it didn't alarm me.

Your phone is still new and should still be under warranty - try bringing it back to the store with the official receipt and have them replace the device based on the issue you're experiencing.

 

[v535]

I got this cellphone new yesterday, is currently updated with the last firmware and related, yesterday at night the cellphone started having this issue where I couldn't see the lock screen just black with some color dots but if I slip my finger I can hear how it unlocks, I have to press the button a few times before showing the actual unlock screen.
Is it something I have to send it to get repaired/ask for warranty or I can solve it by rolling back the updates?

Are you sure you bought 820 instead of 830 since 820 has been discontinued in 2014.