FIORI Leave Request Withdraw - error after send

Hi All,

I'm getting strange message. Scenario is Withdrawing leave request which is already approved (Or created directly in 2001).

User trying to "Withdraw" leave request getting error on popup "An error has occurred" after I click on Send button and web page stuck.

But workflow triggered backend for approval no issue at all.

Not sure this error message from Backend/Gateway/UI5?

Debugged in backend it seems no wrong. Searched SNOTE no luck.

Anyone has faced this issue, any help greatly appreciated.

Please refer to the error print screen.