FDM is generic component, and so we should be able to use 4.11.XX version along with TDM portal 4.10.XX version. However, when we did sanity testing on FDM 4.11.XX version for masking sample tables we see Java related issues which needs to be fixed.
TDM Portal 4.10.x
FDM 4.11.x
It's true that FDM can be run as an independent/standalone component. However, TDM Portal uses the FDM masking engine on the backend when running masking jobs from TDM Portal. Therefore, there are dependencies when TDM Portal is used.
Because of upgrades to Java in TDM 4.11, and FDM 4.11, you cannot use FDM 4.11.x with just any TDM Portal 4.10.x build release. You must be running TDM Portal 4.10.268.0 or greater.
Upgrade the TDM Portal to TDMWeb-4.10.268.0, so that you can use provided fixes in the latest FDM 4.11.x
TDM patches are available for download at the Test Data Manager (TDM) Support Patches page.