Creeper and skeletons banners can be created without patterns

If you put a banner of any color on the loom and press in the empty pattern space you can create a banner with the creeper pattern or the skeleton pattern

What I expected to happen was...:
No pattern be selected

What actually happened was...:
A very hard to get pattern appears

Steps to Reproduce:
1. Get yourself any banner and put it in the loom
2. Pic any dye an put it in the loom
3. Click on the empty space at the end of the patterns list and it will appear