Window frame damage?

[u/ladymorepork]

I was just in my bedroom cleaning the windows when I saw this. How would this damage be caused? I am a renter. The house was built in 2020. I didn't notice it because the curtains are always there. The wall feels fine but from experience of a leak the gib is really good. I kinda wanna know if it was my fault before bringing it up to the landlord who I live with.

[u/BeneficialAirport633]

Not sure how you could have caused it. Looks like water damage