ngx.var.VARIABLE is empty after rewrtie_by_lua

Hello,
Location block-
` location /api/abc/ {

            rewrite_log on;
            include upstreams/allCors.settings;
            include upstreams/proxy.settings;
            proxy_pass http://xyz/api/abc/;
            set $rId '';
            set $aId '';
            rewrite_by_lua_file $lua_base/abcAccess.lua;
            rewrite ^(.*)$ $1?rId=$rId&aId=$aId break;
    }`

In the abcAccess.lua file, I set the rId and aId after some processing by using ngx.var.rId = some value and ngx.var.aId = some value.
I can even see that this is correct by using ngx.log in the same file.

However, in the rewrite directive of nginx, the rId and aId are empty.
I have set "rewrite_by_lua_no_postpone" to "on" in the http block.
The rewrite log also shows rId and aId being set in the abcAccess file first and then the rewrite directive being executed.

Why are the Ids empty?

My openresty version -1.7.10.1

Start with the provided location block and abcAccess.lua, then trace the interaction between rewrite_by_lua_file, rewrite_by_lua_no_postpone, and the following rewrite directive. Use the rewrite log and ngx.log output to compare variable values at each phase. Done means explaining why rId and aId are empty or documenting a confirmed fix for OpenResty 1.7.10.1.