I didn't mention I also tried setting DHCP query frequency to normal which also didn't help. I have to use Merlin software as I use some of its special functionalities so it's not an option to switch away from it. Will just use the Chromecast via LAN until it's hopefully fixed. Anyway thanks a lot for your inputTry these settings. I set my DNS server to google 8.8.8.8 and 8.8.4.4
I also set DHCP query frequency to normal. I attached screenshots.
And make sure your using the current ASUS firmware.