Challenging Tracefile SACKED.PCAPNG

Part of the the Sharkfest Virtual 2020 event was a CTF PCAP (CTF PCAP files) challenge provided by Sake Blok.
One of the challenges was to analyze a pcap called sf20v-sacked. And beside the normal challenge question found some questions for me personal inside the sf20v-sacked file.
The Questions are:
- Why is #2945 right or wrong and can we really answer this?
- And what is strange with packet #2280?
Would be glad to here your opinion about this.