Mylis Maran, in quest for Hlan Oek Tribunal Temple has a buggy script. The buggy part in TR_m7_HO_TT_03_MyRaranNPC script is this:

; disable until quest happens
if ( GetJournalIndex TR_m7_HO_TT_03 < 10 )
    if ( GetJournalIndex TR_m7_HO_TT_03 != 100 )
        if ( GetDisabled == 0 )
            Disable
        endif
    else
        if ( GetDisabled == 1 )
            Enable
        endif
    endif
endif

The script causes Mylis Maran (TR_m7_Mylis Raran) to disappear, if the quest is not started. However, the part where she gets enabled, will not execute, if the quest has been started already.

How to reproduce the bug:

Visit the Raran Ancestral Tomb before starting the quest. This will disable the NPC and prevent enabling her later, after starting the quest.

Edit: Also, it seems TR_m7_HO_TT_03_RaranNPC has the same bug. I've been in the Sasamsi Egg Mine before, so the script did run once, and Malkur Raran doesn't automatically get re-enabled either.