I pulled a sandbox using Salesforce CLI extensions for VS Code using sfdx : Retrieve Source in Manifest from Org command. Later when I right clicked on classes folder and selected SFDX: Retrieve Source from Org command, new classes created in sandbox recently does not get retrieved. Only the classes that are already present in the classes folder gets updated. Is this a known issue?

Command that runs:

sfdx force:source:retrieve --sourcepath d:\VS Code Workspaces\ENGAGE\uat\force-app\main\default\classes