This is probably a bug that @nanocodebug has recently chased down. It is probably not charging at all. Does it charge when you connect the charger before turning it on? Then it should continue charging when you turn it on in that state.
The problem is that when the charger’s 5V is not a higher level than the 5V that is output by the Pocket’s USB port (in “on” state), the charger isn’t recognized by the PD chip. Apparently I have to redo the PD logic in the system controller firmware to fix this. I didn’t find this issue before shipping because it never happened in the lab/with our chargers.
Edit: more background Cannot charge if powered up - #8 by nanocodebug