I have the same problem with the same versions of software.
The simplest example could be this one(with errors on load):
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In[231]:= << HighEnergyPhysics`FeynCalc`
Loading FeynCalc from C:\Users\stanislav.iablokov\AppData\Roaming\Mathematica\Applications\HighEnergyPhysics
FeynCalc 8.2.0 For help, type ?FeynCalc, open FeynCalcRef8.nb or visit www.feyncalc.org
Loading FeynArts, see www.feynarts.de for documentation
During evaluation of In[231]:= Loop::shdw: Symbol Loop appears in multiple contexts {FeynArts`,HighEnergyPhysics`FeynCalc`Loop`}; definitions in context FeynArts` may shadow or be shadowed by other definitions. >>
During evaluation of In[231]:= FeynAmp::shdw: Symbol FeynAmp appears in multiple contexts {FeynArts`,HighEnergyPhysics`FeynCalc`FeynAmp`}; definitions in context FeynArts` may shadow or be shadowed by other definitions. >>
During evaluation of In[231]:= FeynAmpList::shdw: Symbol FeynAmpList appears in multiple contexts {FeynArts`,HighEnergyPhysics`FeynCalc`FeynAmpList`}; definitions in context FeynArts` may shadow or be shadowed by other definitions. >>
During evaluation of In[231]:= PropagatorDenominator::shdw: Symbol PropagatorDenominator appears in multiple contexts {FeynArts`,HighEnergyPhysics`FeynCalc`PropagatorDenominator`}; definitions in context FeynArts` may shadow or be shadowed by other definitions. >>
During evaluation of In[231]:= FeynAmpDenominator::shdw: Symbol FeynAmpDenominator appears in multiple contexts {FeynArts`,HighEnergyPhysics`FeynCalc`FeynAmpDenominator`}; definitions in context FeynArts` may shadow or be shadowed by other definitions. >>
During evaluation of In[231]:= GaugeXi::shdw: Symbol GaugeXi appears in multiple contexts {FeynArts`,HighEnergyPhysics`FeynCalc`GaugeXi`}; definitions in context FeynArts` may shadow or be shadowed by other definitions. >>
During evaluation of In[231]:= NonCommutative::shdw: Symbol NonCommutative appears in multiple contexts {FeynArts`,HighEnergyPhysics`FeynCalc`NonCommutative`}; definitions in context FeynArts` may shadow or be shadowed by other definitions. >>
During evaluation of In[231]:= Optional::opdef: The default value for the optional argument a:f s_.:F|S|V|T|U|SV contains a pattern. >>
During evaluation of In[231]:= Optional::opdef: The default value for the optional argument a:f s_.:F|S|V|T|U|SV contains a pattern. >>
During evaluation of In[231]:= Global`PolarizationVector::shdw: Symbol PolarizationVector appears in multiple contexts {Global`,HighEnergyPhysics`FeynCalc`PolarizationVector`}; definitions in context Global` may shadow or be shadowed by other definitions. >>
During evaluation of In[231]:= Global`DiracSpinor::shdw: Symbol DiracSpinor appears in multiple contexts {Global`,HighEnergyPhysics`FeynCalc`DiracSpinor`}; definitions in context Global` may shadow or be shadowed by other definitions. >>
During evaluation of In[231]:= Global`DiracTrace::shdw: Symbol DiracTrace appears in multiple contexts {Global`,HighEnergyPhysics`fctools`DiracTrace`}; definitions in context Global` may shadow or be shadowed by other definitions. >>
FeynArts 3.7 patched for use with FeynCalc
In[235]:=
Contract[FV[p, \[Mu]] MetricTensor[\[Mu], \[Nu]]]
Out[235]= Contract(p^\[Mu] g^(\[Mu] \[Nu]))
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Instead of contracting it gives out Contract(p_mu, g_mu_nu).
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