AFAIK there is one such example but it’s from a song and, as we know, poets sometimes deliberately {pabHa’} (“follow the rules wrongly”) for rhetorical or poetic effect:

  yoHbogh matlhbogh je SuvwI'
     Say'moHchu' may' 'Iw
  The blood of battle washes clean
     the warrior brave and true. (Anthem)

Other examples of two {-bogh}’ed verbs modifying one noun  all use {‘ej}:

  romuluSngan Sambogh 'ej HoHbogh nejwI'

  Romulan hunter-killer probe (KCD)

  SuDbogh Dargh 'ej wovbogh

  The tea that is SuD and light. (KGT)

  quvbogh 'ej valbogh tIqDu' tIQ
  ancient hearts of honor and wisdom (PB)

There is also an example of two {-bogh}s referring to the same subject noun, but they appear in different clauses:

  quv Hutlh HoHbogh tlhIngan 'ach qabDaj 'angbe'bogh
  A Klingon who kills without showing his face has no honor. (TKW)

--
Voragh, Ca'Non Master of the Klingons

_____________________________________________________________

From: SuStel

On 3/8/2021 8:07 AM, mayqel qunen'oS wrote:

I know that the usual way of using two -bogh clauses on a noun is by joining them with 'ej:

HoHbogh 'ej Qaw'bogh nuH

weapon which kills and destroys

But is there any rule which is actually being broken if we wrote the above without the 'ej?

HoHbogh Qaw'bogh nuH

weapon which kills which destroys

Why would writing something like this be wrong?

Since a relative clause is treated grammatically like a noun, doing this breaks no rules. But it's never appeared in canon, and it doesn't appear to be something that Klingons do.

Look at your English translation: weapon which kills which destroys. There's no rule in English that disallows that phrase, but it wouldn't be said in English. You'd say weapon which kills and destroys. Your phrase breaks no rule, but it's also not right.

-- 
SuStel
http://trimboli.name