In order to understand what is causing the leak, we will first need to determine where it is coming from.
If the leak is between the Straw Spout and the PPSU bottle, check that the replacement seal is securely in place. Simply press gently on the seal and run your fingers along the rim. In addition, you may wish to wait for 5 seconds before attaching the spout to the bottle in order to release any air pressure from warm liquids.
If liquid comes out from the Upper Straw, it may be a result of pressure build-up from warm liquids, or the straw attachment is damaged or worn out. This can occur from general wear-and-tear or vigorous cleaning. Good news is, we have replacement straws available. When wear-and-tear is observed, please replace the Upper Straw immediately. We recommend silicone parts to be changed every 3 months.