In response to your comment "In my own case, I mistakenly cashed the reimbursement, which may make me liable for taxes."
Receiving a check meets the principle of "constructive receipt." In other words, cashing the check isn't the inciting event, receiving taxable income is the inciting event. Whether you cashed it or not, if a portion of the payment (i.e. interest) is taxable, that occurred when the payment was readily available to you.
