Plugin fails to compile in 4.11 due to redefinition errors

Plugin fails compile in 4.11 / 4.12 due to redefinition of class/struct type (locally). AH user reported LNK2005 error when compiling in 4.11

Regression:
YES? - Project with the attached plugin compiles without error in 4.10.4 but fails compile in 4.11.2 and 4.12 Preview 3

1. Download attached Zip file
2. Create new code based project
3. Add Plugins folder to project directory
4. Unzip attached file into Plugins folder
5. Right click .uproject and Generate Visual Studio project files
6. Open .sln
7. Compile

Result:
Added plugin will compile in 4.10.4 but fails compile in 4.11.2 and 4.12 Preview 3

Expected:
Project compiles after adding plugin files