You can do a lot of weird things with ZLL devices because ZLL is the only zigbee profile which does not require a coordinator at all. that’s why bulbs can be stolen, because they weren’t really owned by the first network to begin with.
HOWEVER–the SmartThings hub does not use ZLL, and doesn’t work with touchlink. At all. It is a ZHA network instead, with a SINGLE coordinator (the smartthings hub) which establishes the network and owns the devices joined to it.
There is no way to steal a ZHA only bulb, or any of your other ZHA devices like a zigbee doorlock or a zigbee sensor. None of those use touchlink. Once they join your SmartThings network they’re owned by your smartthings hub until you individually reset the device. Then they are available to join to a different network. But they can’t belong to two at once. Similarly, the SmartThings hub can never belong to the hue bridge’s network: ZHA devices do not join ZLL networks, mostly for security reasons.
Per the standard, ZLL bulbs will fall back to a ZHA profile ( typically on a different endpoint) When joined to a ZHA coordinator. The problem is, they are still open to touchlink commissioning on their ZLL endpoint, which is why they can get stolen back.
But once the ZLL device has moved back over to the ZLL network, it will no longer carry the ZHA messages. And again, the smartthings hub itself doesn’t use the ZLL profile at all.
So bulbs reporting to the hue bridge no longer respond as ZHA devices to the SmartThings network.
It might be theoretically possible to get the ZLL endpoint in one physical bulb to join the hue bridge and the ZHA endpoint In that same physical bulb to join a smartthings network, although I doubt it because of the way device reset works. But even if you could make that happen, you would not have joined the smartthings hub to the hue bridge network, you would just have one bulb that was joined to two different zigbee networks, using two different zigbee profiles, from two different zigbee endpoints.
It wouldn’t be A is connected to B and B is connected to C so there’s a path from A to C.
It would be A is connected to B1 and C is connected to B2. B1 and B2 might physically be housed in the same device, but there would be no path from A to C and they would remain on two different networks.
It’s just the way the profiles work.