For most of KRT stuck issue, you may want to open a JTAC case to find out a bug/PR.
However, there're a few common things to look at:
1. If ARP is resolved for next-hop
2. If you have reachability to the protocol next-hop
3. In some static route configuration, you have used an invalid next-hop, for example, a broadcast address, like 192.168.1.255/24. You may want to check your configuration for the IP 23.248.248.18