If she's part rotti, look up about rotti vocalisations, they can be a very vocal breed.

I've a half staffy, half rotti cross. Who is very vocal. I had two behaviourists and an agility trainer before I learnt to accept I didn't need to teach him not to growl!

He'll play growl, he'll growl to tell me some things out of place, he'll growl to start a game (with me or other dogs). He'll grumble when I scratch his bum! He's never bitten another dog or person. But he will growl if another dog is growling at him, particularly if he's on lead. He hasn't escalated from growling to anything more, and he always calms as soon as he or the stimuli is removed.

He doesn't look like a rotti, but when we went to a rotti socialisation day, it was the first time I met other dogs as vocal as him. Not all rotti's, but I was talking about my not knowing how to teach rufus not to play growl, when I was introduced to a couple of owners with dogs like Rufus!

If the dogs out of control ( flailing everywhere, panicked) that different to a " growl grumble grumble growl" for a steady dog, that's showing you he found a hedgehog in the garden (and managing not to touch it)

Rufus did growl the first time he had a pig ear. For us, I could safely treat him for letting me take it, then give it back, repeat a few times. This was when we got him a year ago. He was 7 months then. And we've never had an issue since.

I'm slowly learning that a dog that communicates lots may scare some other owners, but actually is a dog thats giving you loads more time to do something before he feels over threshold.

Tldr: some dogs growl quicker than others, but might just be communicating with you earlier. Rotti's are wierd, rotti mixes can be unexpectedly wierd!