Many languages distinguish between inclusive and exclusive first-person plural pronouns (“we”). (Click or tap here to see more details)
The inclusive “we” specifically includes the addressee (“you and I and possibly others”), while the exclusive “we” specifically excludes the addressee (“he/she/they and I, but not you”). This grammatical distinction is called “clusivity.” While Semitic languages such as Hebrew or most Indo-European languages such as Greek or English do not make that distinction, translators of languages with that distinction have to make a choice every time they encounter “we” or a form thereof (in English: “we,” “our,” or “us”).
For the first, second and fourth parts of this verse (“we did not follow,” “we made known,” and ” we were eyewitnesses” in English translations), translators typically select the exclusive form (excluding the addressee).
For the third part (“our Lord Jesus Christ” in English translations), translators typically select the inclusive form (including the addressee).
Source: Velma Pickett and Florence Cowan in Notes on Translation January 1962, p. 1ff.