Looks like a regression in 3.5.0-26. Booting 3.5.0-25 (Linux bhnbu 3.5.0-25-generic #39-Ubuntu SMP Mon Feb 25 18:26:58 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux) does not show the problematic behaviour on my system.
Looks like a regression in 3.5.0-26. Booting 3.5.0-25 (Linux bhnbu 3.5.0-25-generic #39-Ubuntu SMP Mon Feb 25 18:26:58 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux) does not show the problematic behaviour on my system.