camelfilename and camelfilenameonly are distinct properties used by the Camel file component. One includes the entire path, the other is just the name of the file. More details on properties used by that component can be found here:
Camel is case-insensitive with property names and SY is case-sensitive. If there is a case where an existing property is actually converted to lowercase, then that's an issue. Please document that case (preferably with a reproducer app) and file a JIRA.