Why do a group of Companions sometimes narrate a verbal hadith with a single text, while many of the hadiths about miracles that were witnessed by hundreds are narrated by only one Companion?

Whoever experiences whispers (waswas) must repel them from the outset, especially if they relate to 'aqidah (creed). If they lead to a doubt, it is obligatory to inquire about it and seek evidence to refute it. There is no issue regarding the authenticity or inauthenticity of a hadith (definition), because the essence of the miracle and the totality of miracles are established by continuous transmission (tawatur) and by inference. The miracles of the Prophet, peace and blessings be upon him, are numerous. Some are established by moral tawatur, like the widely known generosity of Hatim and the hospitality of Al-Ahnaf, while others are verbally transmitted through tawatur, all of which indicate the truthfulness of his message.