I found a bug in SuperTux "tobgle road" 0.6 powerups, the first guy have 1second in his run.

That's not a bug. Whenever you see a "run" by the "player" with the name N/A, that means that the specific combination of category and level (with or without combination of different subcategories) is not meant to be ran at all, so the moderator added a fake/filler run, so other runners will not submit a run themselves. Usually the fake run goes with a comment which explain why the category cannot be played, but it isn't mandatory.

An example of this case which I did myself, can be found here: https://www.speedrun.com/mr_bree_returning_home/Level_1#Hardcore In this example, the game has several modes/difficulties, but some levels in the game are unaffected by this. So, doing level 1 in hardcore is equivalent of running the same level in normal mode, so I added a fake run in the redundant category.