I have a user who has the T410 with the nVidia graphics adapter. I have updated the BIOS and nVidia software to the latest version with the same issue.
Upon reboot or startup in the docking station connected to an NEC 22" wide screen (1680x1050) monitor connected to DVI 2, the machine witll launch windows at full resolution. About a minute or so after login the resolution will switch to 1440x900 and the windows properties will not allow a higher resolution to be chosen.
If I click the advanced button in the display properties or open nView, the resolution will auto switch to 1680x1050.
When the NEC was connected to DVI 1, the LCD would lose its signal a minute after login. Its almost like the machine is auto setting to a "clone view" utilizing the DVI 2 + Thinkpad display after login.