Adapter engine issue in channel at SAP-PI 7.31

Issue: We are facing issue with adapter engine while changing the engine type at channel level SAP_PI.

We have different engines based on projects ,We created channels pointing to specific engine for ex:QXX. During QXX down/ upgrade we switched it to central adapter engine from Specific box (QXX).

while activating the channel it throws an pop-up saying cancelled because that channel is used in multiple ICO's ,even after changing ICO's of that related channels.

After cancellation pop-up when we open the channel and checked it automatically switched back to QXX even after changing to Central engine.

Please let me know in case anyone has faced/have solution to it .