Product Variations mixed all Attributes

I have a Product-variation with over 30 Variations but only two attributtes. With 30 Variations all works fine, but if I add one more (31) all attributes are mixed up on the product page.

I tested this with two themes, so has to be the plugin.

You can simple test it Example:
Attributte: color -> red | blue | green
Attributte: number -> 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10
Now make variations of all products – doesn’t matter if you do it auto or manual.

now add 2 numbers mor 11 | 12 and add variations “red 11” and “red 12” – check Product page, if you select “blue”, number 11 & 12 is also visible but if you remove 2 or more variations, only attributes are visible who has a combination.

Why is this and how can I change this?