I also see weirdness on a E4200 V1, latest firmware, 5GHZ WPA-PSK2, AES
It also does weirdness at work (IBM Network/Cisco AP's, not sure of model, LEAP auth).
Has anyone found a fix for this problem? I've been experiencing the same problem since I activated my EVO LTE in early June. The first update did not fix it, is another one on the way? I too am using a Linksys (Cisco) router, its an older model, but like others have said I have had no issues with any other devices (original EVO, EVO 3D, Nexus 7, ThinkPad, etc.) only the EVO LTE. HTC has got to fix this!!
A new update is in the works, but we haven't heard when it's going to be released yet. It's been a month since the last update so I'm thinking any day now we should hear something official in the Updates Blog at the bottom of this forum.