NGINX serving multiple angular applications - static files missing error

Problem with the regexes, try

location ~ ^/admin/.*\.(html|js|css|eot|svg|ttf|woff|woff2|png|gif|ico|jpg|jpeg)$ {
    try_files $request_uri $request_uri/ =404;  
}
location ~ ^/monitoring/.*\.(html|js|css|eot|svg|ttf|woff|woff2|png|gif|ico|jpg|jpeg)$ {    
    try_files $request_uri $request_uri/ =404;  
}

oh, and don't forget to restart nginx and clear browser cache.