Mojko, the description in the game manual doesn't actually address the scenario that's causing confusion here. Some cards that share a token keyword with Far sight (
Luna the sorceress,
Crimson hawk,
Flame lord are likely examples) can cause that shared keyword to hit 100 due to the Far sight effect. Those of us who are familiar with the order of operations know that this happens because Far sight's effect happens last.
However, the game manual's description doesn't explain this. Rather, it claims that because the played card has the keyword (true) and because the counter reached 100 as a result of playing it (also true), the effect should occur (false).
The manual needs to take this possibility into account. It may not be a common occurrence, seeing as Far sight increases the lowest counter, but it does happen. Additionally, most Far sight decks are only setting one or two keywords since Far sight's behavior favors doing so, so newer players may witness their opponents' counters reaching 100 with no effect and be confused as to how or why.