GitVersion: GitVersionTask 5.1.1: object reference not set to an instance of object.

Fails with 5.1.1, downgrading to 5.0.1 works.

GitVersionTask.targets(56,9): error : Object reference not set to an instance of an object.

When building this csproj

<Project Sdk="Microsoft.Build.NoTargets/1.0.85">

  <PropertyGroup>
    <TargetFramework>netstandard2.0</TargetFramework>
    <IncludeBuildOutput>false</IncludeBuildOutput>
    <UpdateAssemblyInfo>false</UpdateAssemblyInfo>
    <SuppressDependenciesWhenPacking>true</SuppressDependenciesWhenPacking>
  </PropertyGroup>

  <PropertyGroup>
    <developmentDependency>true</developmentDependency>
    <PackageRequireLicenseAcceptance>false</PackageRequireLicenseAcceptance>
  </PropertyGroup>

  <ItemGroup>
    <Content Include="build\*">
      <PackagePath>build\</PackagePath>
    </Content>
    <Content Include="buildMultiTargeting\*">
      <PackagePath>buildMultiTargeting\</PackagePath>
    </Content>
    <Content Include="tools\**">
      <PackagePath>tools\</PackagePath>
    </Content>
  </ItemGroup>

  <ItemGroup>
    <PackageReference Include="GitVersionTask" Version="5.1.1">
      <PrivateAssets>all</PrivateAssets>
      <IncludeAssets>runtime; build; native; contentfiles; analyzers</IncludeAssets>
    </PackageReference>
  </ItemGroup>

</Project>