Linux Xubuntu 13.10, x64, kernel 3.11.0-15-generic
AMD Radeon HD6850 1Gb
Broken: 2.69.11 77290fc
Short description of error
When you input a number in the bevel weight field, Blender changes this number to something else. From my understanding it happens because internally bevel weight parameter has 8 bit precision or 0-255 range, but bevel weight number field shows it as 0.000 to 1.000 range. So for example when you set it as 0.5, Blender first accept this number, but later when you quit edit mode, it convert it to 0.498. Such behavior is inconsistent and very confusing for a user. Also it makes precise beveling difficult. Blender should either use exactly inputed number or not accept invalid input. The solution here I believe would be to change internal precision to 0.000-1.000 range or change bevel weight number field field to 0-255 value slider. This problem also appear when you use Edge Bevel Weight through Ctrl+E menu.