similar issue. Chargepoint Home Flex set to 48 A. Rivian switches to 42A. It's on a 60 A line.
Anyone have a solution or answer yet?
You should first make sure that your SOC is "down a little" so that the Rivian will actually accept a charge.
If it isn't, just raise the "Max charger level" in the Rivian (example: move it from 70%-85%). This is only temporary and you don't need to let it actually attain that level.
There are dip switches and/or a potentiometer in the Chargepoint.
There is a setting in the Charger section in the Rivian (not the app)
Set both of these to 48 amps
If it reverts to 42, do the following:
Unplug the charger from the Rivian
Reboot the Rivian (Left steering wheel button + Emergency Flasher--hold down until screens turn off, then release)
Turn off the breaker to the Chargepoint.
After the Rivian reboots, set the Rivian to 48 amps in the Charger section
Turn on the breaker to the Chargepoint
Plug the Chargepoint into the Rivian
See what happens. It may take 4 to 5 minutes to get to where it's going amp-wise.