Devices only seem respond to MQTT requests generated with their own MQTT tokens. The owner’s credentials cannot be used to pub-sub to owned devices, despite having full access.
e.g. User Andrew (id 0xDEADBEEF, token 0x0F0F0F0F) owns 2 devices: Cranberry (id: 0xCCCCCCCC, token: 0xBBBBBBBB) and Raspberry (id: 0x11111111, token: 0xAAAAAAAA). To be able to PubSub to Cranberry and Raspberry, Andrew has to use (id: 0xCCCCCCCC, token: 0xBBBBBBBB) and (id: 0x11111111, token: 0xAAAAAAAA) instead of being able to do this using his own token.
Can you make the device topics be accessible by owners and/or other users with the right set of permissions?