When using a Proprties file with credentials, the injected property file has carriage returns "^M" (in my example, test3 is the injected credentials):

cat -vet /home/jenkins/.myconfig
test1=test^M$
test2=test^M$
test3=XXXX$

If I don't use a credentials but simply properties, the file does not have carriage returns:

cat -vet /home/jenkins/.myconfig
test1=test$
test2=test$