Ok, so i have an Oracle 18c client on Windows installed. My TNS_ADMIN environment variable is set to the location of my tnsnames.ora file.
C:\windows\system32>echo %TNS_ADMIN%
C:\oracle\product\18.0.0\client_1\network\admin
I then edit the tnsnames.ora file to remove an entry. I hit save and then tnsping that entry again. It still works. What gives? I removed that entry? If I rename the tnsnames.ora file and try it I get the TNS-03505 error so tells me I am using the correct tnsnames.ora file.