caf pshuta touching a letter below
I think that here is no shayla, and scraping the negiya is permitted.
a. the ngiya is minor, thinner than the foot, and not the whole width of the foot of the caf, so a clear distinction between the letters was always there.
b. a simple assumption may be made that the sofer started the lamed from the vav protruding above, then continued doing the gag - so there never was a possibilty of it resembling a beis.
c. another simple assumption [even if the sofer did the gag before the vav] that the sofer continued the gag and rounded it downward, so even if picking up the kulmus before finishing the other parts of the lamed, the caf could not have been a beis.