Many protocol analyzers require special drivers or place the NIC into monitor/promiscuous mode. When used this way, the original driver stack may be altered or replaced. Afterward, if not correctly reloaded, the adapter may lack full 802.1X support or required encryption features. This is likely the case here - Mary's WLAN adapter is still under the control of or affected by the analyzer's NIC driver, which doesn't support PEAP properly.
References:
CWSP-208 Study Guide, Chapter 6 - Protocol Analysis Limitations and NIC Driver Issues CWNP CWSP-208 Objectives: "Troubleshooting WLAN Authentication and Driver Conflicts"