Inconsistent icons in the user panel

I'm not sure if this is the right department, or if it would be better in suggestions. I'm wondering why the bell icon is empty inside, while, for example, the message icon is full. My suggestion is to make the bell icon full as well, like the message icon, or have both of them empty inside, and when a message or notification arrives, they become full. What do you think?

My suggestion:

Or empaty:

With notification:

No messages or notifications - blank icons
With notifications and messages - full icons.

Or full icon or blank icons.