Patches on my california basement wall
What your seeing is called efflorescence which are mineral deposits from moisture which sometimes seeps through exterior walls. Even though the basement walls may be inset from  the main level water will migrate through soil layers. It appears that the other side of that wall is in contact with compacted soil. Even if it was water-proofed during construction moisture can sometimes seep through.
I don't think it looks serious. It would be different if water was obvious or pooling on the interior. At this point you can treat the interior walls with water-proofing material such as Drylok or Flex Seal. Although it might solve the efflorescence issue it won't keep moisture from seeping into the wall from the soil. The other option is to excavate the exterior of the wall and treat it with water-proofing which would be labor-intensive or prohibitively expensive.
As I indicated I would try to keep exterior groundwater away from the foundation and if the efflorescence is a major concern for you can treat the wall with an interior water-proofing product.