Unfortunately I haven't tested it with UE4.27.
If your retargeting settings are correct, you can check that the IK goal location you created is in the correct bones.
Other than that, you should delete any unused retargeting data.
Maybe @Bassline303 has an opinion on this.
When importing the CC character, have you tried importing directly by selecting the UE4 skeleton?



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As far as I know I have not touched the IK goal information. How would I check/change that?

I drag and drop it into the folder while the engine is running like the tutorials say, and I select the skeleton I want. I don't know of another method.