Random "vision" bug on minimap

So I'm not too sure if this post will meet the requirements as I'm not quite sure how to reproduce the bug, will try to reproduce and update throughout the week.

The bug I've been experience shows a portion of the mini map to have vision, imagine the size of what you would see in lane standing there, but with no allied champion in the area. Any enemy minions passing through this area CANNOT be seen (with the exception of the siege minions as these can be seen in fog of war.), same applies for enemy champions.

May not seem to be too influential, however causes confusion on how much you can actually see forward if you enter the area once the bug has appeared. Clicking on the mini map in the position that the "vision" appears to be will shown to have vision, but nothing will pass show up (as described above for the minimap). Standing on the edge of the zone, it will appear that your champion has increased vision on the length of the lane you are in. However enemy minions will then suddenly emerge from the closest point at which you actually have vision (same applies for enemy champions). Super misleading and has almost gotten me killed many times. I suspect it is an issue with expiring wards but as mentioned, I will be testing this.

Thanks,

Godaisora