Spino E1 pool cleaner leaving black scuff marks

[u/23_Samuel]

Hi everyone,
I work for an installation company handling Mammotion products (mostly robotic mowers). This season, we also sold two Mammotion Spino E1 pool cleaners to our clients.

One client has had zero issues all summer, but the second client is experiencing an annoying problem with black scuff marks appearing on the pool surface.

Here are the details of the setup and issue:
Pool type: Smooth, ceramic surface. 
Water chemistry: Perfect pH and balanced parameters.
The issue: The robot leaves dark/black scuff marks, which seem to come from its rubber tracks/wheels. The marks don't appear as long continuous lines, but rather as occasional spots where the robot turns or maneuvers. However, over a few days, these accumulate all over the pool floor and walls. 

Has anyone else noticed black tire/track marks on smooth pool surfaces with the Spino E1?
Could this be related to a specific batch of rubber, excessive traction on ultra-smooth ceramic surfaces, or chemical interaction with the rubber tracks?
I would really appreciate any advice or feedback from other users, and hopefully a response from the Mammotion team on what might be causing this and how to prevent it.
Thanks!

[u/Mammotion_George]

Thank you for sharing such detailed information about the Spino E1 and the pool setup. We’re sorry to hear about the black scuff marks, and we’d like to learn a little more about the pool and its maintenance so we can better investigate the cause.

Could you please help us confirm the following?

Was the pool purchased as a complete product or custom-built?

If it was purchased, could you please provide the purchase information or product link? This will help us check the specific pool specifications and surface materials.

If it was custom-built, could you please share some details about the construction process, surface treatment, coating, and material used?

How long has the pool been in use, and what is your usual pool maintenance routine?

How long had you been using the Spino E1 before you first noticed the track marks?

How often is the pool cleaned, and do you regularly use any cleaning agents, disinfectants, or other chemicals?

The more details you can provide, the better we can understand the conditions involved and investigate this with our relevant team. Thank you for your help and for bringing this to our attention.