The scheduling conflict occurred after an uplink was received.
8:15:2:233|INFO| GW:00:80:00:00:a0:00:03:89|FRAME-RX|Parsing 1 packets
8:15:2:234|DEBUG| GW:00:80:00:00:a0:00:03:89|FRAME-RX|DATA: 408400000680f903029cceb0b4e1f4a8a91ed860eb04bc
8:15:2:234|DEBUG| GW:00:80:00:00:a0:00:03:89|FRAME-RX|FREQ: 903.700000 MHz DR0 RSSI: -111 dB SNR: 25 cB
8:15:2:234|DEBUG| GW:00:80:00:00:a0:00:03:89|FRAME-RX|TYPE: Unconfirmed Up
8:15:2:235|DEBUG| GW:00:80:00:00:a0:00:03:89|PACKET-RX|ADDR: 06:00:00:84 FCnt:03f9
Without uplink traffic the class C packets would have been scheduled without conflict.