I definitely don't think her behavior is okay, and I am definitely concerned about it. I'll admit to taking the easy way out for the grooming this time. Olive has other issues we're working on and I am (rightly so, I believe) concerned that forcing her to cooperate will pull the rug out from the trust we've been building. I don't put up with biting, and I didn't with Olive, either (she was corrected with my screeching and a leash pop which I very rarely do and she knows I mean business when I do), I just didn't continue to force the situation. With most other dogs I've dealt with I would have gotten out the Ace bandage, made a muzzle, and got on with it. And that is what I will do with her if she gets that attitude again.
FWIW, she was perfectly well-behaved at the groomer today, no muzzle needed. So yeah, I realize that means I am the one who is being the weak one here as far as the grooming is concerned. Still not forcing anything while we work out her other stuff but I think I might try her with the soft muzzle outside grooming sessions to see how she responds.
As you know, Toby has similar issues to Olive, its sounds like grooming is one of them. Toby and Olive are different dogs so what works with one may not work for the other, but here's what I did.
First, I spent a small fortune on grooming brushes, trying to find the best and gentlest brushes, combs, etc. that my 'sensitive' guy wouldn't mind.
I spent hours upon hours (over a looong period of time), patiently trying to desensitize him using those expensive brushes and make grooming a positive experience for him, giving him praise, treats, ect. In return he continued to kicked me, refused to stand, refused to lie down, hold still, etc. Often while standing he'd suddenly become what I affectionately call 'blob dog' when suddenly all of the bones in his body dissolve and he pools on the floor. My favorite is when he suddenly out of the blue screams bloody murder like I've mortally stabbed him even though I'm barely touching him, then he swings his head around like he's going to bite me. Every time he startles me so badly because he catches me so completely off guard that I'd swear he shortened my life by a few years.
I'd finally had enough after taking him to a groomers to find out his bad behavior didn't exist for them at all. I stopped putting up with his crap, used a stern voice or sharp 'NO' when he was being difficult or acting like he was going to bite, then continued to praise and give him treats for his good behavior.
Toby will always be a pain in the rear end to groom, but he's much easier better now that I've stopped treating him like he might break and don't tolerate his shenanigans. At the end of the whole thing he still loves me.
You have to decide what is best for Olive and for your relationship with her, but a little bit of tough love when patience doesn't work might help.
Or if you're to worried about it then you can buy her a muzzle and acclimate her to that.