When toggling visibility of frames, it seems Figma forgets to update the eye icon:
In this record, you can see the “+” icon on the canvas toggling, but the eye icon doesn’t switch between the open/closed eye.
As you can see, it happens with frames only - I toggled the visibility of another layer in this recording, where you can see the open/closed eye switching.
It’s a small, cosmetic bug, but it’s quite confusing if the layer you’re toggling isn’t in the viewport at the moment.