01
Another customer shares the budget
Imagine a product offering 100W with one device, then 65W plus 30W with two. Adding a device changes what the first port can promise. These figures illustrate one possible allocation, not a rule for every 100W charger.
02
A new menu, sometimes a restarted output
The charger may advertise new capabilities or restart an output while reconfiguring its power circuitry. USB PD does not universally require every port to disconnect whenever a cable is added. Independent circuits and allocation strategies can behave differently.
03
Compare the conditions before and after
Check the product’s shared-output table, the PD messages and measured VBUS. A device without a battery may reboot during a short interruption. Repeated dropouts with no connection changes deserve a separate investigation.