Error sourcing etc/bashrc with relative path

If I try to source the etc/bashrc file without specifying its full path I get "-bash: cd: etc/bashrc: Not a directory". To reproduce do:

dhi@argos3:$ cd /home/dhi/OpenFOAM/OpenFOAM-plus dhi@argos3:/OpenFOAM/OpenFOAM-plus$ source etc/bashrc -bash: cd: etc/bashrc: Not a directory dhi@argos3:~/OpenFOAM/OpenFOAM-plus$ source /OpenFOAM/OpenFOAM-plus/etc/bashrc dhi@argos3:/OpenFOAM/OpenFOAM-plus$

Same problem in v1612+