The stock LPN client for Mesh SDK v4.0.0 throws NRF_MESH_EVT_SAR_FAILED when replying to a publication set message via a friend node.
All code, reproduction data and log output is here: https://github.com/siriobalmelli/nrf_mesh_4.0.0_lpn_SAR
I also tried to implement the suggested answer from this thread:
... this did not work, see this commit:
Please see https://github.com/siriobalmelli/nrf_mesh_4.0.0_lpn_SAR/blob/master/README.md#reproduce-mesh-lpn-friendship-sar-bug step 2.
I am making sure that GATT is not connected:
1. On BubblyNet App by clicking "disable proxy" after provisioning
2. On nRF Mesh App by manually changing to the light server as a proxy so messages *must* go through LPN
We have tried to reproduce the issue on our side, and haven't had any luck. One of our developer checked-out the your repo, modified the example name RTT output and tested the LPN example. He did not see the SAR_FAILED event. He used NRF Mesh Android app version 1.2.1. Have you tried with a different phone? Both Android and iOS?