Simple display problem; some edges do not show up

Another effect I recently noticed: if I rectangle-select some edges before and behind the "missing ones" an export them to a file, reimport them, the missing edged are visible!

I attached a video with the edges displayed one by one. After some time with every newly displayed edge some previously shown edges were hidden or previously hidden edges were shown again.

My Draw Test Harness (DRAWEXE.EXE) shows the same behaviour.
Can anybody reproduce this?

---snip---
# Display a large number of lines

#Category: Visualization BUG "invisible lines"
#Title: Display a large number of lines

pload ALL

vinit View1 w=1024 h=1024
vsetdispmode View1 1
vtrihedron trihedron1
vsize trihedron1 400
vclear

#vtop
set scale 0.1
set vpprojx 0.0
set vpprojy 0.0
set vpprojz 1.0
set vpupx 0.0
set vpupy 1.0
set vpupz 0.0
set vpatx 4995
set vpaty 500
set vpatz 0
set vpeyex 4995
set vpeyey 500
set vpeyez 0.0001
vviewparams -scale $scale -eye $vpeyex $vpeyey $vpeyez -at $vpatx $vpaty $vpatz -up $vpupx $vpupy $vpupz -proj $vpprojx $vpprojy $vpprojz

set NB 1000

proc draw_lines {{distance 10.0}} {
# set colors to corner spheres
for {set i 0} {$i < $::NB} {incr i} {
set x [expr $i * $distance]
set ya 0.0
set yb 1000.0
set z 0.0
vertex v1 $x $ya $z
vertex v2 $x $yb $z
edge e$i v1 v2
vdisplay -update e$i
puts "$i: $x $ya $yb $z"
}
}

puts "Start test lines"
draw_lines 10.0
vfit
---snap---