In Half Life 2: Episode Two, during the Riding Shotgun Chapter, when entering the barn (where the Advisor is supposed to be), the action that should be taken by Alyx is not triggered.

Processor Information:
    Vendor:  GenuineIntel
    Speed: 2403 Mhz
    4 logical processors
    4 physical processors
    HyperThreading:  Unsupported
    FCMOV:  Supported
    SSE2:  Supported
    SSE3:  Supported
    SSSE3:  Supported
    SSE4a:  Unsupported
    SSE41:  Unsupported
    SSE42:  Unsupported

Network Information:
    Network Speed:  

Operating System Version:
    Ubuntu 12.04.2 LTS (64 bit)
    Kernel Name:  Linux
    Kernel Version:  3.5.0-18-generic
    X Server Vendor:  The X.Org Foundation
    X Server Release:  11203000
    X Window Manager:  Compiz
    Steam Runtime Version:  steam-runtime-release-i386_2013-05-08

Video Card:
    Driver:  NVIDIA Corporation GeForce GTX 560 Ti/PCIe/SSE2

    Driver Version:  4.3.0 NVIDIA 319.17
    Desktop Color Depth: 24 bits per pixel
    Monitor Refresh Rate: 59 Hz
    VendorID:  0x10de
    DeviceID:  0x1200
    Number of Monitors:  1
    Number of Logical Video Cards:  1
    Primary Display Resolution:  1920 x 1200
    Desktop Resolution: 1920 x 1200
    Primary Display Size: 20.39" x 12.76"  (24.02" diag)
                                            51.8cm x 32.4cm  (61.0cm diag)
    Primary Bus: PCI Express 16x
    Primary VRAM: 1024 MB
    Supported MSAA Modes:  2x 4x 8x 16x 

Sound card:
    Audio device: VIA VT1708S

Memory:
    RAM:  5969 Mb

Miscellaneous:
    UI Language:  English
    LANG:  en_US.UTF-8
    Microphone:  Not set
    Total Hard Disk Space Available:  177648 Mb
    Largest Free Hard Disk Block:  41929 Mb

Installed software:

Recent Failure Reports:
    Fri May 10 16:07:58 2013 GMT: file ''/tmp/dumps/assert_20130510180739_1.dmp'', upload yes: ''CrashID=bp-902c7ac4-c8d0-4279-bf16-ff2ba2130510
    ''
    Fri May 10 16:13:51 2013 GMT: file ''/tmp/dumps/assert_20130510181329_2.dmp'', upload yes: ''CrashID=bp-b66e5b3d-bedf-4363-b13a-a6c162130510
    ''
    Fri May 10 16:53:04 2013 GMT: file ''/tmp/dumps/assert_20130510185242_1.dmp'', upload yes: ''CrashID=bp-51331ed2-5723-4af8-ac43-c66922130510''
    Fri May 10 16:56:47 2013 GMT: file ''/tmp/dumps/assert_20130510185624_2.dmp'', upload yes: ''CrashID=bp-9d34e0f1-daac-4c76-aba9-32d1e2130510''