Describe the bug
Spring Tool Suite 4.18

For nested enums:

in list/set/map properties structs:

if enum type used in C.E form (not E with C.E import) properties autocomplete is not work.
Wrong substitution:

and no value suggestions:

In Spring Tool Suite 3.9.22 all works fine:

To Reproduce
Try use properties/yaml autocomplete in attached example.zip project.

Sample

Attach example.zip project.
example.zip