There's a 14 day expiry on that domain name (at least on 8.8.8.8, google's DNS server). So you should be good for something close to that, my guess, up to 14d - 6h from when the BGP routes were dropped.
So your main issue is for .eg urls that are not cached in the DNS hierarchy you are using. Basically the root servers will direct you to one of (approx) three eg. root servers. These are probably down, or unreachable (due to BGP drops).
To my (basic) understanding of DNS, once your local server knows that ns[1-4].google.com is responsible for this domain, it doesn't need to go to the eg./eg.com. root servers to get updates.
And yes, you're probably getting directed to a "local" version of google.com.eg.
I use to work on the team that maintains the webserver that serves Google websearch. google.com.eg (and any other google search domain) can be served out of many of Google's datacenters, in various places around the world. The user is sent to the "closest" data center that can serve their request, to minimize latency. Country-specific domains don't have to be served out of the local country (that would be pretty unmanageable, given the number of country specific domains Google has).
So your main issue is for .eg urls that are not cached in the DNS hierarchy you are using. Basically the root servers will direct you to one of (approx) three eg. root servers. These are probably down, or unreachable (due to BGP drops).
To my (basic) understanding of DNS, once your local server knows that ns[1-4].google.com is responsible for this domain, it doesn't need to go to the eg./eg.com. root servers to get updates.
And yes, you're probably getting directed to a "local" version of google.com.eg.