PHP PDO oci extension stopped loading

After going through our most recent deployment, pdo_oci stopped loading up with the rest of the php PDO extensions…
None of the apache (except for hostname) and php configurations were changed in this deployment.

This was the error I was seeing in console:

could not find driver

I have QA and Production environments with the same configurations:

extension=php_mysqli.dll
extension=php_oci8.dll       ; Use with Oracle 10gR2 Instant Client
extension=php_pdo_mysql.dll
extension=php_pdo_oci.dll
extension=php_pdo_odbc.dll
extension=php_pdo_sqlsrv_54_ts.dll

+

QA:
PDO shows mysql, oci, odbc, sqlsrv; as expected

Prod:
PDO shows mysql, odbc, sqlsrv; missing oci

At this point, I am not really sure what else to do. Everything in the configs looks fine and I have tried restarting the services and whatnot.
Have checked all the php.ini dir and extension dir paths.

Has anyone encountered this issue before?
I would like suggestions…

PHP 5.4 x86
Windows Server
Apache 2.2
I have used each of the db access drivers before on these servers successfully.