I'm in the same boat. My charger drops to half amperage after 5-10 minutes of normal charging. I've already called that number listed above and started a case. My buddy had the same exact problem and received his new/replacement wall charger last week. I think they'll wind up sending me a replacement soon.
This is what Tesla support told me to do to get the newest update for my connector:
I have also attached instructions for you to be able to get connected to your unit. After you have proceeded with getting unit connected to your home Wi-Fi make sure you leave Wall Connector unplugged from the car for two hours. After the two hours reset the breaker and attempt to charge, if you still have the same charging interrupted give us a call back.
Here are the steps you would use to connect to the Wall Connector Broadcast and Commission the Wall Connector.
Sign into the Wall Connector broadcast by first resetting the Wall Connector breaker for at least 5 seconds, and cycling it back on.
This will start the Wall Connector broadcast. The broadcast is only visible for 5 minutes. If you are not successful in connecting to the broadcast, you may need to reset it again to restart the broadcast.
Search in your Wi-Fi networks for the signal:
The Wall Connector Password is: It is case sensitive (all CAPS)
Once you have signed into the broadcast, then sign into a Chrome, Firefox or Safari page 192.168.92.1 to see the Wall Connector Commissioning page.
Here is the link to the online support page with the information to add the Wi-Fi network in and commission the wall connector:
Once you are logged in, follow these steps to change network settings:
Step 1: Select the breaker size, click next or continue
Step 2: Select your home Wi-Fi network and enter your Password
Step 3: Complete the commissioning.
Step 4: If you get a message that shows that it is partially configured go back through and change the breaker to a smaller breaker size and complete the commissioning. Then complete the commissioning again with the correct breaker size and it should now show that the system is fully configured.
Just an FYI, I found out that you can bump up the amperage from half to almost three-quarters of original amperage before the overheat condition occurres. Other words on the car display if you normally charge at 48 amps and it goes back to 24 amps try 30 amps and see if that charges okay without dropping down. If it does work you might be able to go up to 32 amps. It does not hurt the car with this overheat condition.
I have noticed that if I stay in the car the charge remains at 48 but if I leave and the car locks with walkaway lock the charge decreases to 24 within a few minutes.
I have checked for loose connections, nothing is hot and the wires from the breaker to the connector are copper. These are things that have been posted as potential causes. Anyone else noted this. I have not tried not locking the car. That's my next step.