Side indicator lights don't work, but do with Hazards button
 

I'm new to owning a Porsche (a few weeks in), and have a 2008 Cayman S.

I purchased some updated LED side indicator lights and installed them last week. Purchased online, and they were pretty much "plug and play", advertised as no error codes etc.

When I installed them I checked they were "blinking" fine, and been driving since.

Today I noticed I couldn't see them flashing when I was stopped near a glass window, and have discovered they don't flash when by turn indicators are on. The front and rear indicators work fine.

The side ones also work when I put the hazards on. So it's just when I'm driving and use the turn signals.

I'm not much of a hands on kind of guy, don't know much about wiring/electrics, but these didn't really have anything to do other than plug the connector in, so I don't think I could have installed them incorrectly.

Any thoughts? Faulty/cheap lights themselves?