In every shorted-yoke case I've seen (in 30+ years in the trade), the raster was shrunken both vertically and horizontally in addition to the taper.
In the photo of the Bug Eye however, the frame begins with a bright line at full horizontal sweep, then abruptly transitions to about 1/2 horz sweep during the remainder of the vertical scan.
Dunno what else could be "modulating" the H scan in such a manner. Maybe some vertical leakage getting into the grid of the horz output tube
. My bet would still be on the yoke.