TL 2019 - inconsistent processing of environment variable TEXINPUTS

[Johannes Kunde]

Hi TeX Live community,
I recently installed TeX Live 2019 on a Windows 10 machine and observed 
a strange behavior (at least in my eyes) with the environment variable 
TEXINPUTS.
I process LaTeX documents with XeLaTeX and in order to find all 
necessary files in my specific LaTeX document structure, I need to 
adjust the preconfigured PATH setting. To achieve this, I set TEXINPUTS 
as follows:
TEXINPUTS=.;my/path/goes/here//;

When I set TEXINPUTS as a windows environment variable in the OS 
settings, everything works as expected.
But when I try to set it via the appropriate config-file 
${basedir}/2019/texmf.cnf, TL messes up my whole PATH setting and 
terminates with “! LaTeX Error: File `my/file.tex' not found.“

The TL documentation recommends to make all changes to the defaults in 
${basedir}/2019/texmf.cnf:
https://www.tug.org/texlive/doc/texlive-en/texlive-en.html#x1-560007.1.2

Is this a bug in TeX Live or do I miss something?

Best regards
Johannes