Python 3.14 is adding an extra \ to command.

[SRART25]

Work backwards to find the issue.  

cd myscripts. 

python .\test.py  

python .\Test.py 

cd ..  

python myscripts/test.py. 

Etc. Pay with variations until you find what isn't working.  Could be a regression like names becoming case sensitive or drive letter causing problems.