VTserver problem (bug?)

[Charles]

I sometimes use vtserver to download disk images to the RL02's on my 
PDP-11/23+.  Takes quite a while at 9600 baud, too :)

But there is some kind of bug that always appears at the same point, in the 
middle of the next 100K block after "6600K written".
The data transfer stops (no more head motion/ready light flicker on the 
RL02), and the character that vtserver uses to indicate a write operation 
just repeats endlessly and rapidly until I kill it.

Does anyone else encounter this limitation, and if so, how did you fix it? 
Fortunately I haven't wanted to image a disk that's more than 2/3 full so 
far... I make sure to squeeze the disk in SIMH before transferring the 
image. But it'd be nice to be able to image a full (10 MB) RL02 and not have 
to worry about it failing.

Any ideas?
thanks
Charles