I have only done dropdown type of options, but I’ve added more than 10 values for one option.
Or are you talking about 11 custom options for one product? Or maybe 11 total custom options?
1. Upon trying to add 11th custom option to the same product, I’m taken away the ability to add checkboxs/drop-downs/radio-buttons. As ridiculous as may it sound, all I needed to do was add another custom option, which brings everything back to normal. Wierd, but at least I’m glad it’s now working.