How short is too short to stay at a job

I just started a job (same company Ive been at for 15 years) about a month ago and unfortunately it is nothing like what the hiring manager described it would be. It’s a corporate role and I am basically doing the same job I did 10 years ago in my career. I reached out to my network and quickly found a great opportunity more in lined with what I want to do. Should I tell my boss and apply? or wait it out and see how my job morphs? would I burn any bridges if I left so soon?

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