At 99% the gateway has already loaded and is enforcing the new policy.
Once the gateway has completed loading the new policy by 98%, the Check Point management components (SMS, SMEvent, Log Servers) perform an object database sync at 99%. If you are hanging for awhile there, check the configuration and network reachability/bandwidth for any of these other components. Do you have a Check Point management object still defined that doesn't exist any more or is unreachable? That will cause a delay at 99%. If these management components exist but have poor network connectivity to the SMS or a shortage of resources on them such as CPU/memory, that can also cause a delay at 99%.
Gaia 4.18 (R82) Immersion Tips, Tricks, & Best Practices
Self-Guided Video Series Coming Soon