18 month old digs nails on everything out of frustration normal yes or no?

Since I can remember she has been digging her nails at everything I would think by now she would have grown out of it. She has her 18-month appointment coming up and I will ask her doctor but has anyone dealt with this before?

She can be completely normal and suddenly I'll see her dig her nails at my phone screen until her nails break. I do keep her nails short by the way she breaks her already short nails. I tried redirecting but then she'll just grab something else and dig her nails on something else..

She is hitting all her Milestones by the way.

Maybe I'm just being paranoid but the fact that she can do this for a long time and keep doing it until her nails break it's kind of concerning to me

Edit: i realized she hums while she's going it.