what disease or problems we encounter without the special functions of the bones

In order to access the special event with a Celebi in Pokémon HeartGold, it must be a Celebi that has the "Fateful Encounter" flag in its summary. If it does not have "Fateful Encounter" in its summary then it will not activate the special time travel event in "HeartGold."

It's a message you'll find in the Pokemon Info.

It basically means that the Pokemon was received at a special event at a place IRL or over WiFi.

If you have a Pokemon that says "Fateful Encounter", it is an Event Pokemon.

Common prepositions that can be used with "encounter" include "in," "during," "through," "on," and "at." For example: "She had an encounter with a bear in the woods," "We had an encounter during our trip," "They had an encounter through a mutual friend," "I had an encounter on my way to work," "He had an encounter at the restaurant."

The word encounter is both a noun and a verb.

Examples:

He had a strange encounter on a train.

You will encounter many obstacles.