Is my stepdaughter’s phone use and online access a safeguarding concern?

[Girls62]

My step daughter is in year 6 and we’ve had a lot and back and forth about her phone with her mum. Her phone use is very high when at mums 9-11 hours per day and her profile is set as an adult. recently we have discovered she’s been watching some very inappropriate videos ‘how to be a good mistress’ ‘how to seduce your friend’ ‘did me and my best friend do it in bed’.
we have asked mum to remove YouTube, TikTok, Snapchat off the phone as she isnt old enough and I believe allowing her to access these things is a safeguarding issue, I can’t understand why mum would want her to have access to these things.
does anyone know if this is a safeguarding concern and if there’s anything as a family we can do to get her off these age inappropriate sites and have an age limit on her phone

If Mum won’t listen I’d speak to the Safeguarding lead at school. Not only is she at serous risk from exposure to inappropriate material and risk from grooming etc but she could be sharing inappropriate information with peers.
The over use will probably be affecting her presentation, mood and performance in school. There may already be some concerns.
if she makes inappropriate searches on school laptops or iPads these will be picked up as schools have rigorous systems in place.
Mum is failing to safeguard her daughter so the other parent needs to step up and ask for help.

Wildly inappropriate.
How would her mum feel about you buying her the Pinwheel phone or similar? (For almost at end of primary/ finishing sats). Then her current phone her mum can take to CEX or something…?
I’d also talk to school expressing you’re concerned about accessing inappropriate materials. I’m not sure they’d actually do more than a group discussion. Whilst it’s a very poor parenting choice and detrimental for children…. She’s likely not the only one in her class. It’s wild. At my DDs school (also year 6) most are anti-phone. There’s chats about smart watches, dumb phones and phones like Pinwheel for secondary in year group chat etc But my friend with a DD same age, says quite a lot of her class have got one and caved in year 5!! I really struggled to comprehend it really.

I don’t think she’d be happy tbh, mum seems to be on board until SD goes back to her house and convinces her to let her back on.
I can’t get my head around it either, I just keep thinking why would you want your baby girl looking at sexual things on the internet.

I am not anti phone my son does have one but it’s heavily monitored, age restricted to his age, sends me a message is he even types a word he shouldnt and he has to request all apps through my phone. He has no social media and has no access to YouTube
I do believe children can have phones but also be safe and protected

We're having the same problem when my step son goes to his mums. I have put time limits/age restrictions etc on his phone but when it all cuts off, she just hands hers over.

I cannot get my head around it.

We can’t put age restrictions on because she’s connected to her mums family sharing, we have no control over the phone at all.
and it’s getting to the stage she’s texting her mum saying we’re taking her phone and she needs her to tell us not to..
i feel like I’m having things happen under my roof that I don’t agree with and it’s making me feel quite uncomfortable

That's so worrying OP, completely inappropriate. Christ mine were still playing with baby annabell in year 6!

Same. The mum is in agreement to all that we ask for (no YouTube, no social media, restrictions on adding randoms) then tells them the override password as soon as they get back to her house. We can change the password but still, it’s so frustrating and just rubbish parenting.