If there is one person who knows about USB Type-C more than any of us and likely some of the folks that designed the spec itself, it has to be Benson Leung. The Google engineer has been fighting a war against poorly made USB Type-C cables and chargers by reviewing them over at Amazon.com and saving ill-informed buyers from buying them.

Considering that some of the wrongly spec’d USB Type-C cables can permanently damage your smartphone or tablet, this is not a small feat.

The engineer has now made a revelation that is going to surprise many. In a Google+ comment, Leung says that all Qualcomm Quick Charge 3.0 compatible USB Type-C chargers in the market violate the USB Type-C specification. More specifically, the engineer says the USB Type-C spec sheet clearly forbids any proprietary charging method that changes the vbus beyond 5v. Qualcomm’s Quick Charge specifically does that to get to its 9V and 12V power outputs.

This is why Benson recommends against buying any Quick Charge 3.0 compatible USB Type-C chargers and even phones like the LG G5 and the HTC 10 because simply put they don’t comply with the USB Type-C spec.

USB Type-C itself also supports fast charging through USB Power Delivery, which is capable of delivering voltages as high as up to 20V, and unlike Qulacomm’s Quick Charge 3.0, this is not a proprietary charging method and open for all OEMs to implement. Google has used this same technology on the Nexus 6P and Nexus 5X.

So yes, the LG G5 and HTC 10 do feature a USB Type-C port, but they are not USB Type-C compliant. Similarly, Qualcomm Quick Charge 3.0 certified USB Type-C chargers that are available on the market are not spec compliant with the Type-C specification and can harm your other Type-C devices.