All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
Our answer, in brief, is that there may be two Ahadeeth transmitted with the same chain of narration, but one of them is classified as Saheeh (authentic) and the other is classified as Dha‘eef (inauthentic). One of the narrators may be principally trustworthy, but his narration became confused as he grew feeble-minded in old age. One of his students may transmit the narrations he had heard from him before he experienced such a state of poor memory and other narrations afterwards. In this case, the narrations reported on his authority before he became of weak memory in old age are classified as authentic, while those reported after experiencing memory deficiency are classified as inauthentic, although they share the same chain of narration. For example, ‘Ataa’ ibn As-Saa’ib experienced memory deficiency in old age. One of his students who transmitted his narrations was Hammaad ibn Salamah, and he heard from him some narrations before he suffered memory deficiency and other narrations afterwards. Scholars of Hadeeth classified the narrations reported on his authority before memory deficiency as authentic and those reported on his authority afterwards as inauthentic.
Moreover, there may be two Ahadeeth reported with one inauthentic chain of narration, but one of them is classified as Hasan (sound) or authentic because it was reinforced by another supportive Hadeeth. Scholars of Hadeeth label this category of Hadeeth as Hasan or Saheeh Lighayrihi (sound or authentic due to other corroborating reports). Meanwhile, the other Hadeeth would be classified as inauthentic because it is not reinforced by another corroborating report.
This is the case with the two Ahadeeth mentioned in your question. Both Ahadeeth have the same chain of narration, which is inauthentic because it was narrated by Darraaj from Abu Al-Haytham. As for the second Hadeeth, which reads: “Tooba is a tree in Paradise as big and huge as a distance being crossed in one hundred years. The clothes of the people of Paradise come out from its coverings (calyces),” Al-Albaani said about it in As-Silsilah As-Saheehah, “It is classified as Hasan Lighayrihi (sound on account of corroborating reports).” He cited other Ahadeeth that attest to its meaning. Therefore, it is classified as Hasan due to other supportive Ahadeeth reinforcing it. Lastly, we advise you, dear brother, to strive in seeking religious knowledge.
Allah Knows best.