Is the wireshark as per BACnet Standard 1.18?
Can see one issue in BIPv6 frames. Forwarded NPDU shown as malformed if the sender is as per BACnet Standard 1.18. Forwarded NPDU packet has discrepancy as per BACnet Standard.
What is your version of Wireshark? Can you share the capture on a public share, e.g. Google Drive, DropBox etc.?