I added a product and other colors appeared?

Short answer: The other versions of the product (Men, Women, Junior) were added with it, and some did not exist in the colors you had chosen: they arrived with their own.

Cause

Two mechanisms combine.

First, a product available in several versions is added with all its versions — see What is a multi-version product.

Second, suppliers do not offer the same colors on every version: a shade available in Men may not exist in Junior. When that happens, the version concerned is added with the colors it does have, rather than being left out. The message warns you that this occurred.

What to do

Nothing urgent — your shop is consistent. But do check, version by version, that the colors kept suit you:

Open the detail sheet of each version from the selection, using the small (i) icon on the thumbnail.
Adjust the colors — three at most per version. See How do I choose the colors of a product.
Uncheck “Apply the below action also to the other versions of this product” if you want the change to affect only the version you have open.

This is a good moment to check your logos too: a logo meant for light products will not show on a deep color that arrived this way. See My logo is not visible on the product.

Going further

How do I choose the colors of a product — the limit of three and the display order.