Conflict with discount code

Hi there, At first thanks for your useful plugin ??
Our business logic is that all customers should use the discount code in orders.
In some cases some users after applying discount code in cart/check-out page, they can not deduct wallet balance for partial payment and the check box disappeared.
I’ve tested all coupons setting and also tera wallet setting.
Please note that just some accounts/users have this problem and for example in my own account I can use both of discount and deduct wallet balance !
Do you know how can I debug it or find the solution?
Thanks for your helping…