I'm not aware of any such rule. Perhaps the confusion is with the rule that you can't put a Type-5 noun suffix on any non-final noun in a noun compound?

There is at least one canonical example of a locative -Daq nested within another:

{tlhIngan juHqo'Daq tlhIng yoSDaq 'oH toQDuj chenmoHlu'meH Daq wa'DIch'e'.}

"1st Construction Site: The Kling District, Klingon Home World"

Source: Klingon BoP poster

http://klingonska.org/canon/1998-11-01-bop.txt

{tlhIngan juHqo'Daq tlhIng yoSDaq} probably isn't seen as one 4-noun compound that forms a single locative, but rather two 2-noun compounds forming two locatives, one of which is more specific than the other.

(Granted, this poster also violates the rule mentioned above, by describing "wing lights" as {telDaq wovmoHwI'mey}. That might be explained as a shorthand used for labeling purposes, though.)

//loghaD