The limiting/throttling/USPR is absolutely not related to pack temperature. As you can see, my battery temp was consistently increasing throughout the charge session, yet I was able to restore normal charging amperage by cooling the connector and cable. Also, note that no other Tesla connected to any stall at the site for the duration of the data collection.
Additionally, I noticed that in lieu of cooling the cable you can simply switch stalls from A to B (on the same cabinet) and this will restore a normal charge rate. So, it has nothing to do with the car, it has nothing to do with the cabinet overheating, and
it has everything to do with the temperature of the cable/connector from the pedestal.
View attachment 206716
Bottom line: Yeah, this sucks. I mean, SpC used to be a set and forget experience. Plug the cable into an unpaired stall and walk away. Now, it appears that Tesla Engineering has tightened the thermal limits and aggressively tapers the charge rate if they see the connector getting too warm. While I appreciate the reasons for this, it significantly degrades the user experience and I urge Tesla to come up with another solution. (What happened to liquid cooled cables???)
Unfortunately, the workaround for this means that you must stay with your car the entire time and be ready to act in case the rate begins to decline at a rapid rate. I witnessed this behavior ~50% of the time. Sometimes supercharging works great, but in others not so well.
I had this happen at the BRAND NEW supercharger at Anderson's Split Pea. So even new equipment is no guarantee that this will not occur.