Why is this an issue?

The argument passed to FreeAndNil must be an instance of a TObject descendant.

Prior to Delphi 10.4, the signature for FreeAndNil is untyped. This erroneously loose contract allows any variable to be passed into FreeAndNil, which will cause a runtime exception.

How to fix it

Remove the incorrect call to FreeAndNil - non-object types are either managed or have an alternative way of freeing associated memory.

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