This ball possession is not uncommon at all.....I had a female I imported like this. She was not aggressive AT ALL - just if she got it, it was hers! You could get bitten holding it up high as she would jump and grab - got a few bruises that way, never an actual bite.....she was the same way with a sleeve...you could NOT let her possess it and take it off her easily.
Always have a second ball and trade her, get her to out the ball by offering the other one....very common way to get through this. I always told people with pups from this line to start off with "two ball" because of this tendency to possession in this female's progeny.
Csabre Sch1, Hexe Sch2, SG Bengal, Lynx, Komet, Kira HGH & Kougar v Wolfstraum ~ Ziberia IPO1 ~ ATB Basha IPO3, Danger Sch1 RH SAR ~ Kougar & Kyra, Cito, Alice, Kelsey, Ret ~ Fenja