Windows CMD batch 'if' statement string check works sometimes with case-sensitivity

I have a simple CMD 'if' check:

set param=%9
IF %param%=="true" ( 
...

param is coming from Python and is a Boolean which can be True or False and which str converted version is again starting with upper-case: "True" or "False" The problem here is when I run mentioned CMD script as Windows batch file on my PC, it works, despite the case difference and absence of quotes, but on other PC it works only if I add quotes and write uppercase "True":

IF "%param%"=="True" ( 

The only difference I can find on my and the other PC is that my Windows language is English and other one uses German. Both use Windows 10.

What can cause the CMD to work differently?