It is not common for a brand new motorcycle to creep forward with the clutch fully pulled in. The phenomenon you're describing, where the motorcycle continues to move forward despite holding the clutch lever in, is known as clutch drag or clutch slippage.
Clutch drag can occur due to several reasons, including:
Clutch Cable or Hydraulic System Issues: If there is excessive slack in the clutch cable or if the hydraulic clutch system is not adjusted properly, it can cause insufficient disengagement of the clutch plates, leading to clutch drag.
Clutch Plate Wear or Misalignment: In some cases, the clutch plates may wear prematurely or become misaligned, causing the clutch to engage partially even when the lever is pulled in. This can happen on a brand new motorcycle if there was a manufacturing defect or if the clutch assembly wasn't properly installed.
Oil Contamination: If the clutch plates get contaminated with engine oil or other fluids, it can create friction and prevent proper disengagement of the clutch.
Since you mentioned that this issue arises only after the bike has been warmed up, it's possible that the clutch plates are expanding slightly due to heat, causing them to engage partially. This can happen if the clutch plates or springs are not functioning optimally.
Given that you have a brand new motorcycle, it is advisable to take it to an authorized dealership or a qualified motorcycle mechanic to have it inspected and rectify the issue under warranty. They will be able to diagnose the problem accurately and address any potential manufacturing defects or assembly issues.
It's important to address this issue promptly as clutch drag can affect the control and safety of the motorcycle. Until the issue is resolved, exercise caution and be mindful of the motorcycle's behavior to ensure safe riding.