There is a SOLIDWORKS Configuration Suppress Features checkbox in the advanced options of the Configuration Properties, and it is checked by default. What is the purpose of the Suppress Features option?
If Suppress Features were unchecked, then any features added in other configurations will be unsuppressed (included) in this configuration.
By default, however, the box is checked, so new features added in a different configuration will be suppressed (not included) in this configuration. The active configuration is protected from those new features, unless the user explicitly instructs SOLIDWORKS to configure a new feature to be unsuppressed in specified configurations including this one.
It’s usually best to leave the suppress features box checked unless there is a good reason not to. Otherwise, you could end up with a mess to tidy up, mainly involving tracking down and suppressing unwanted features.