I have the same problem on some of my routers. Not all.
https sites like https://wellsfargo.com
can not be rendered. Other sites like https://crucial.com
are very slow to render.
I do not have a router workaround. The problem is exacerbated by some third party routers at the client location. Like a netgear. The DNS proxy does not seem to get information from the my Mikrotik main router and pass on to the client PC. I can ping to domain but cannot pass https:// site to the client.
My only solution has been to replace the client router (ex: netgear) with a mikrotik. I have 600 customers and cannot replace all their routers.
Is there a known issue with Mikrotik - ROS passing https data on to third party routers?