Howdy, Brissie Boy.
The Johannine Comma as the 1John verse is called, has been dodgy ever since Erasmus lost his bet and was forced to insert it in a new edition.
Quoting Metzger-The Text of the New Testament-p101-'Among the thousands of Greek manuscripts examined since the time of Erasmus, only three others are known to contain this spurious passage. they are Greg.88, a twelfth-century manuscript which had the JC written in the margin by a 17th century hand, Tisch.w110 (16th century),and Greg.629 (14th century).