Strange brown water marks on my white plastic cover vaillant ecotec plus 838

[Buysite450]

HI everyone

Had my new boiler about 4 months... it's a vaillant ecotec plus 838...

Today I noticed some browning on the white plastic cover looks like could be water marks... or some sort of lacker issue...

Anyone seen something like this before?

 

[Riley]

Does sound rather odd Are you able to add a couple of photographs to the thread so we can take a look