I noticed with the latest update v4.7.4 on my GL-mt2500 that add blocking seems to have drasticly changed. I was seeing hundred of blocks on my router from various devices on my network. I see Nothing being blocked and when I look at the query log, I dont see many DNS lookusp when I know they are being used.
I saw somewhere in the Reddit that one user always did the factory reset after upgrading the software with GL-inet routers to fix his issues. I can't find the link anymore but I would probably try that. It's nasty I know.
You can backup your settings on the Advanced Settings -> Luci -> System -> Backup / Flash Firmware page. This way if the hard reset doesn't work you can at least re-enable all of your settings from the backup'd archive.
DNS is being captured and stopped by firewall. The nslookup thinks it's checking cloudflare but really adguard is blocking ads.google.com per the rules I set.