Likely there is a "Power" command that is issued as you load the TV page. Learning this code from the native remote will result in a "Toggle." Each time that code is issued the TV will flip from ON to OFF or OFF to ON. You need to use "Discrete" "ON" and "OFF" codes.

I don't use Visio, but I assume that there are Discrete power commands in the RTI IR code database. Most TV's will ignore an "ON" command if they are already ON, however, some will pop something on screen for every power command.