cecil: System.InvalidCastException in Mono.Cecil.MetadataBuilder.GetConstantSignature

System.InvalidCastException: Unable to cast object of type 'System.Byte' to type 'System.String'.

   at Mono.Cecil.MetadataBuilder.GetConstantSignature(ElementType type, Object value)
   at Mono.Cecil.MetadataBuilder.AddConstant(IConstantProvider owner, TypeReference type)
   at Mono.Cecil.MetadataBuilder.AddField(FieldDefinition field)
   at Mono.Cecil.MetadataBuilder.AddFields(TypeDefinition type)
   at Mono.Cecil.MetadataBuilder.AddType(TypeDefinition type)
   at Mono.Cecil.MetadataBuilder.AddTypeDefs()
   at Mono.Cecil.MetadataBuilder.BuildTypes()
   at Mono.Cecil.MetadataBuilder.BuildModule()
   at Mono.Cecil.ModuleWriter.<BuildMetadata>b__0(MetadataBuilder builder, MetadataReader _)
   at Mono.Cecil.ModuleDefinition.Read[TItem,TRet](TItem item, Func`3 read)
   at Mono.Cecil.ModuleWriter.BuildMetadata(ModuleDefinition module, MetadataBuilder metadata)
   at Mono.Cecil.ModuleWriter.WriteModuleTo(ModuleDefinition module, Stream stream, WriterParameters parameters)
   at Mono.Cecil.ModuleDefinition.Write(Stream stream, WriterParameters parameters)
   at Mono.Cecil.ModuleDefinition.Write(String fileName, WriterParameters parameters)
   at Mono.Cecil.AssemblyDefinition.Write(String fileName)

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Built with the latest commit.

I believe the offending line is https://github.com/jbevain/cecil/blob/master/Mono.Cecil/AssemblyWriter.cs#L1915 (AssemblyWriter.cs:1915), however I have no clue about the codebase so I don’t really know what this line is supposed to do or how to debug it. Unfortunately I cannot share the assembly, but please tell me if I can do something to assist.