I will see if I can find it but there was a post earlier stating that SmartThings did a firmware update a while back that separates relayed packets to alleviate that issue.
Here’s the link.
Great comment @JDRoberts . The older OSRAM firmware also has some additional routing problems that has been fixed in the latest production firmware available now via the LIGHTIFY Hub. However even the latest firmware has the “buffer overflow” problem that @JDRoberts mentioned. In an attempt to keep from hitting that problem we have increased the delay between messages sent by the ZigBee library (zigbee.* function calls in the DTH). It can take a little longer for commands like configure or refresh to finish but it is more likely that all the messages will get through successfully.