RTP protocol not recognized

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I am reviewing a pcap file on two different machines. Both are running the same version of Wireshark, but one is running on Windows 10 and one is on Windows 7. The Win7 machine shows a particular group of packets as RTP, but the Win10 machine shows the same group of packets only as UDP. The frame that identifies the RTP protocol is correctly recognized on the Win7 machine, but the Win10 sees that frame only as part of the payload. Any suggestions as to what might be causing one machine not to recognize the RTP?