The assertion that the Punch CVT is unreliable is a common sentiment among some owners and automotive commentators, largely due to initial design choices and perceived refinement issues. However, many owners report good reliability with proper maintenance.
Common Complaints

Lack of Refinement: Early versions were often described as jerky in traffic, noisy, and unrefined, which is contrary to the smooth operation expected of CVTs.

"Rubber Band" Effect: The transmission can produce a loud, droning sound during acceleration due to the nature of how CVTs adjust ratios, a common complaint with older CVT designs.

Durability Concerns: Issues like bad gearbox bearings and, in some rare cases, catastrophic belt failure were reported, leading to expensive complete replacements.

Driving Experience: The use of a start-up clutch instead of a torque converter in some earlier Proton models meant drivers had to adapt to the car's unique behavior, which many found to be a hassle.
Improved Reliability

Despite initial problems, subsequent updates have largely addressed these issues.
Reduced Warranty Claims: Proton has stated that after introducing a revised transmission in their 2019 facelifts, warranty claims saw a reduction of over 80%, indicating improved reliability.

Proper Maintenance: Many long-term owners emphasize that the key to a reliable Punch CVT is diligent maintenance, such as changing the transmission fluid and filters on time (e.g., every 40,000 km or as per the service schedule).

Driving Style: CVTs are not designed for aggressive driving or high power output. Driving smoothly and avoiding "launching" the car can significantly extend the transmission's life.
The reputation for unreliability largely stems from initial generations and insufficient public information regarding updates and proper maintenance procedures. Modern iterations are generally considered more reliable, provided they are maintained correctly and driven as intended.