Trying to delete an INTERRUPTED transfer results in a 500 Internal Server Error

Trying to delete an INTERRUPTED transfer results in a 500 Internal Server Error.

$ waarp-gateway transfer get 8
● Transfer 8 (receive as server) [INTERRUPTED]
    Rule:             test-put
    Requester:        partner
    Requested:        gw-sftp
    True filepath:    /tmp/another-gatewayd.ini
    Source file:      another-gatewayd.ini
    Destination file: another-gatewayd.ini
    Start time:       2021-07-21T03:23:22.745729413Z
    Step:             StepPostTasks
    Progress:         2403
    Task number:      0
$ waarp-gateway transfer cancel 8
unexpected error (500 Internal Server Error): internal database error