I was directed here after opening a ticket with support.
I have a number of the 2018 Smartthings motion sensors. These devices are running a mixture of firmware versions 0x11 and 0x0b. Issues were observed using both versions of the firmware.
I do not use a smartthings hub. Where can I obtain Ota update files, with appropriate metadata if the files are not in ZCL default format?
Network traffic was monitored on a laptop using Wireshark 3 with a USB attached nrf52840 running Nordic’s 802.15.4 sniffer firmware.
The following issues have been
1: The motion sensors do not set the disableDefaultResponse flags on immediate responses (as required by spec), but do not enter fast polling in anticipation of a requested message (which must be generated if the response was not a default response - also per spec).
This causes extra radio traffic to the device. It also consumes buffer space on both the device’s parent and on the device sending the default response. These resources are used for pretty much an entire long poll period.
The firmware should be updated per spec to disable default responses when sending an immediate responses to requests. It may also be worth considering whether to request default responses when generating attribute reports, and also when generating zone status notifications.
2: The power descriptor reports that the device is using mains power only. The power cluster (0x0001) indicates two batteries. On average this is correct 
3: If the OTA client is mistakenly given a broadcast address when attempting to locate an OTA server it will attempt to perform the next step in the OTA process, which is to resolve that address to an EUI-64.
This step obviously does not succeed ; however the procedure immediately retried twice, and then repeatedly at ten minute intervals.
Thanks,
Simon