Apologies for the delay here. Instance not found means that at some point the Jive instance was not able to register with your tile. In order to make this happen, you can issue a "Reconnect to Service" from the Add-On Admin UI. This should send the Add-On re-registration information such that subsequent requests are "known".
As for future feedback, feel free to drop it here in this community. Hope this helps =)
I do know that it was unable to register, it is throwing a 400 error every time I try to and I have been tracking it down. Something is weird with how OpenShift and Jive's sdk apps work together and I am doing what I can to figure it out.
In this case though I was just recommending a change to how the sdk is handling a certain situation based on what I was dealing with. Thanks for the idea though and for the confirmation on where to drop feedback!