A way to forcefully delete a route advertisement filter in NSX-T. Use w/ extreme caution.

DeleteNSXTRouteFilter.sh

echo -n Enter NSX Manager IP:
read nsxmgr
echo -n Enter NSX Manager admin password:
read -s secret

# The below curl command will display logical router id's and display names for those id's.
curl -k -u admin:$secret https://$nsxmgr/api/v1/logical-routers/ | awk -F ': ' '/"id"/{print substr($2,2, length($2)-3)} /"display_name"/{print substr($2,2, length($2)-3)}'

echo -n Enter target router id:
read routerid

rulesbackup=$(curl -k -u admin:$secret --request GET --url https://$nsxmgr/api/v1/logical-routers/$routerid/routing/advertisement/rules)
revision=$(curl -k -u admin:$secret --request GET --url https://$nsxmgr/api/v1/logical-routers/$routerid/routing/advertisement/rules | awk -F ': ' '/"_revision"/{print substr($2,1)}')
#Backup of existing rules just in case ;)
echo $rulesbackup >> rulesbackup.txt

# Uncomment line below if you would like to verify data was recorded.
#cat rulesbackup.txt

# Below curl call will clear out any rules associated w/ the routerid provided.
curl -k -u admin:$secret -H "X-Allow-Overwrite: true" --header 'Content-Type: application/json' --request PUT --url https://$nsxmgr/api/v1/logical-routers/$routerid/routing/advertisement/rules --data '{
"rules" : [
],
"logical_router_id" : "'$routerid'",
"resource_type" : "AdvertiseRuleList",
"id" : "'$routerid'",
"_revision" : "'$revision'"
}'
secret=''