Wix finding duplicate symbol when importing a feature

Question

I get the following error when trying to compile a recently updated to wix 4.04 (from 3.11) project

`Severity   Code    Description Project File    Line    Suppression State   Details
Error   WIX0091 Duplicate symbol 'Feature:ServiceFeature' referenced by C:\DevelopmentRepos\<project>\<project>\Product.wxs(64). This typically means that an Id is duplicated. Ensure all your identifiers of a given type (File, Component, Feature) are unique or use an access modifier to scope the identfier. <project>   C:\<CI Location>\Setup\<project>.Setup\Library.wxs  102`    

this is despite this feature emphatically being only referenced once, even a word search on the entire directory confirms this. I'm also having other issues with components imported via wixlib simply are never found but I'll keep this question pointed. Why could this occur and is it still correct to reference the features as:

    <Feature Id="RootFeature" Title="!(loc.PropertyProductNameShort)" Display="expand" Level="1" Description="!(loc.ArpComment)">
      <FeatureRef Id="ServiceFeature" />
      <FeatureRef Id="CSServiceFeature" />
      <ComponentGroupRef Id="AlarmServiceComponents"  />
    </Feature>

I have tried importing as a componentgroupref, as well as if I simply delete the feature ref I get an empty installer, so I know it isn't being pulled in multiple times somehow.