Bleed works perfectly to account for inaccurate cutting when your artwork overlaps the edge of the media. When you create artwork which snaps to one of the corners, or even one of the edges, there is no perfect solution. Only 100% accuracy will ensure a perfect result.
Here I show eight different ways to add 3 mm bleed on your artwork, ranging from the naive no bleed at all (1) to the sophisticated 45 degree angles (8):
And here I'm simulating (very) inaccurate cutting by moving the artwork 1.5 mm down and 1.5 mm left inside the format:
As you see, none of these solutions offer a bulletproof way to account for inaccurate cutting.
If I had to choose, I think I would go with option 6 (the one you are showing in your example) as it seem to give the cleanest result. But it's up to you. Now you have eight possibilities to choose from.
If I were you, I would talk to the manufacturer and hear if they have any good advice. They must have encountered this issue before.
All this said, please bear in mind that your labels probably are punched with a premade form. This should ensure a higher accuracy than if they were cut in a cutting machine.