Is it normal for the water tank to have water when the Xiaomi Robot Vacuum S40 is opened for the first time?

It is normal for the water tank to have water in it when opening the Xiaomi Robot Vacuum S40 for the first time.
For your reference, the reasons are as follows:
1. The Xiaomi Robot Vacuum S40 undergoes random inspections before leaving the factory, including a water tank inspection in which clean water is added to the tank for verification;
2. After the tank inspection is completed, the water is drained. It is normal to find residual water stains in the tank;
3. This is not a sign of previous use or a defect, but rather a standard part of the manufacturing and quality control process. The remaining moisture is harmless and does not affect the robot vacuum's performance.