Do you know at what SF the nodes start the OTAA? (The screenshot shows SF12, but they might have started with a better SF?)
Do you have access to any low-level logging on the TTOG? I wonder if ERROR: Packet REJECTED, unsupported RF power for TX - 24 could affect the TTOG as well. That problem started after something changed for V2 gateways being handled by something in V3, early this year. I don’t know the details. Maybe the TTOG has been using that route since much longer.
Oh, and is the gateway using 4G or a wired connection? (Maybe latency has increased, making downlinks arrive too late at the gateway? But then regular downlinks would not work either. Are you 100% sure that other downlinks work?)