The freshness seal is designed to preserve the pods optimal taste and reduce the chances of the pod leaking prior to use. Minor leaking during use may result from extreme temperature conditions, excessive humidity, drastic change of attitude or by aggressively puffing on the mouthpiece. 
If your Nikki pod is leaking slightly, you can still vape it by removing the pod from battery and wiping off the liquid before inserting back to your Nikki device.
If you encounter an excessively leaky Nikki pod or continue to experience leaking, please keep the affected pod and contact Nikki care team using the Contact Us Form.