We are aware of an known issue which prevents Pitch 'n Time LE from appearing in Logic Pro X's Plug-in Manager. You will not be able to confirm the presence or validation status of Pitch 'n Time LE via Logic Pro X → Preferences → Plug-in Manager.
Apple has changed the way plug-ins of certain types are shown in the Plug-in Manager of Logic Pro X (10.4.5 and above), and thus Pitch 'n Time LE will not appear in the list of available plug-ins, even when it has been correctly validated, and is available to choose in Logic Pro's Time & Pitch machine.
Ensure you have activated your Pitch ‘n Time LE product correctly via our Pitch ‘n Time activation article. You can then check your instance of Pitch 'n Time LE is validated and working as expected, by selecting it as an algorithm in the Time & Pitch machine, or by navigating to Edit → Time Stretch → Time Stretching Algorithm and choosing Pitch 'n Time LE.
We have raised this issue with Apple and hope they can resolve this visibility issue regarding the specific plug-in type.