2003 Volkswagen Passat Question: More blinker issues

The contacts in the turn signal switch itself are a known issue , though far less common than the flasher unit , which was the subject of a recall on some years/models!
Other than confirming wiring and connections , especially ground wiring , usually solid brown in color , try a switch.

My malibu does this too. I put a piece of card board between my air vent up by the 4 way switch and it stopped. I haven't fixed it yet, but it works.