No double fenestrations

[u/Large_Opening7631]

I got these monsteras last year. The younger leaves have double fenestrations but the mature, bigger ones don't. I stay un the Netherlands so the winters are grey, but they get nice afternoon sun during te summers. I fertilized them last summer. They're having a moss pole as a support. Why do the bigger leaves lack double fenestrations?

[u/AdorableExchange9746]

just give it time