Mcumgr asks for Bluetooth pair when used along with OTS service

[cl2hang]

I need to add the support of FOTA to my application. But, OTS is used in the application which enables BT_SMP by default. It was good before, but once I reimplemented the firmware for the latest NCS toolchain and SDK 3.1.0 (my previous toolchain and SDK is 1.8.1), I found OTS conflicts with Mcumgr in some way. Later I found it's because of BT_SMP which is enabled by BT_OTS. Once BT_SMP is enabled, bluetooth pare will be needed on the client side during FOTA (e.g., when I am using the nRF Connected Device Manager app). No matter I choose pair or not, it just doesn't work.

We can reproduce this issue by using the sample "smp_svr", we can add the Config item "CONFIG_BT_SMP=y" in the "overlay-bt.conf" file to see such an issue.

Thank you for your answer and help.

All the best!