Steps to reproduce
1) Tools - Templates 
2) select Licenses - Default license 
3) Duplicate
4) Rename to license-gplv3.txt
5) the template remains as  ~/6.7//config/Templates/Licenses/license-default_1.txt in the filesystem


The fact that the filename is not changes makes the 
project.license=gplv3 

in project.properties useless. Because the template system will try to use license-gplv3.txt instead

Error reading included file Templates/Classes/../Licenses/license-gplv3.txt 


The workaround is to rename the filename directly in the filesystem but then the template cannot be managed  via Tools - Templates.