No one is waiting for yet another set of corrections in Codex Bezae Cantabrigiensis, but in the recent transcriptions it seems that something has been left out. For example here in Mark 5:8 where there is correction of the nomen sacrum ο ιηυ to ο ιηυς, but in addition, there is a line underneath these two words, which are unique to the Greek text of Bezae. Can it be that the underlining indicates awareness of a variant?
The next one is a couple of lines further down (Mk 5:9, also on the image above). This time it is εστιν that is underlined, which again is a fairly unique reading (Legg adds Π margin). Another one?
The next underlined word is at Mark 5:18 και ενβαινοντος. Legg notes και εμβαντος as a Byzantine variant, but this is not a particularly obvious target. Especially since και ενβαιν is underlined and not the variant part -οντος. So perhaps not.
However the fourth example, five lines down and also on this image, is again a full hit, ο θς for ο κς.
Browsing a little back I notice at Mark 4:24 τα underlined (should be τι) and also on the same page at 4:29 the final two letters of παραδοι (possibly pointing at the reading παραδω).
So what to make of this? In Parker's discussion of 'hand K' (Parker, Codex Bezae , 41) he mentions fourteen 'horizontal strokes in the margin or written area, which cannot be dated'. Are these six examples discussed here part of the fourteen? None has been noted in the transcription of Bezae on the Cambridge University website, though the key to the transcription (on the Birmingham site) has '(K) A symbol used by Scrivener to indicate various later corrections and notes, displayed in this transcription as s.m.' Underlining strikes me as a fairly 'modern' way of marking something, and not every choice of items to mark is particularly exciting. Yet, it is a manuscript feature worth noting.
When someone is tired of looking at dots in the margin of Vaticanus, they may want to turn to underlining in Bezae.