How sound is the Hadith: "Glad tidings to the reformers who, when present, are not recognized, and when absent, are not missed," and is there an addition to it?

This Hadith was not reported with this exact wording. Rather, it was reported with similar wordings by Al-Bayhaqi, in which it was mentioned that the sincere ones are the lamps of guidance, and tribulations are dispelled from them. It was also reported by Ibn Majah that Allah loves the righteous, pious, and unassuming ones, whose hearts are lamps of guidance, and who emerge from every tribulation. Something similar was reported by Al-Hakim, who authenticated it, despite a weakness in the chain of transmission of Ibn Majah.