Component not always applying the priority

Step to reproduce:

• Create a new extension with only one simple class which extends DefaultPDFExportJobRequestFactory.
• In components.txt add something like this {{10:org.xwiki.example.CustomPDFExportJobRequestFactory
  }}. So we expected that this would override DefaultPDFExportJobRequestFactory
• Install this extension on the main wiki.
• Run this simple groovy script:

  {{groovy}}
  println services.component.getInstance(org.xwiki.export.pdf.job.PDFExportJobRequestFactory.class)
  println  services.export.pdf.requestFactory
  {{/groovy}}
  
  Expected: 
  
  The result of the groovy script is:
  

  org.xwiki.example.CustomPDFExportJobRequestFactory@7c1c8420
  org.xwiki.example.CustomPDFExportJobRequestFactory@7c1c8420

  
  Currently:
  
  The result of the groovy script is:
  

  org.xwiki.example.CustomPDFExportJobRequestFactory@7c1c8420
  org.xwiki.export.pdf.internal.job.DefaultPDFExportJobRequestFactory@2581a82e

So it seem that that the custom is not correctly loaded in the PDFExportScriptService.

Workaround: if we install the extension in the farm + we reboot the instance it seem working as expected.