re: Brown Spots on Recently Planted Cucumbers

No, and this is why I directly sow the seeds into the ground, and a lot of them so I can thin later and keep the healthiest plants, but I grow a lot of cucumbers every year on 2 trellises 12+ feet long with no less than 25 plants per trellis.

Check out cucumber fungal/disease issues to see a pic that could match what you are seeing and get an idea how to treat it.