I think this is related, and maybe a good chance to fix this. If you setup you master tag to take a variable src attribute, things go bad if the variable evaluates to the empty string:
in tcl:
set template ""
in adp:
<master src="@template@">
The master tag logic compares "@template@" to the empty string to decide what to do. Obviously "@template@" is never empty, causing a very hard to trace problem.
I discuss the problem more here:
https://openacs.org/forums/message-view?message_id=124554
