Strange redirect to old deleted page

I’m getting a strange redirect to an old deleted page.

If you go to https://www.kohmakguide.com/

You can see in the menu koh mak weather forecast. Before all the pages in that manu where subpages and looked like this
https://www.kohmakguide.com/kohmak/weather/ but now I deleted the page in between (kohmak) and they all work fine except one. If you go with you mouse to the weather link on the sidebar menu and look at the url it looks like https://www.kohmakguide.com/koh-mak-weather/
but when I click on it, it always redirects me to the old page https://www.kohmakguide.com/kohmak/weather/ which is deleted.

What could be causing this?