My GUESS (I have not tested) is this:
When looking at buffs.xml, all the buffs are listed. I'm going to look specifically at "buffLaceration"
The first line of the XML for this buff is:
<buff name="buffLaceration" name_key="buffLacerationName" description_key="buffLacerationDesc" tooltip_key="buffLacerationTooltip" icon="ui_game_symbol_laceration" icon_color="255,128,0">
Looking at some other buffs, say "buffNearDeathProtection", which seems to persist after death, I see this in its first line:
<buff name="buffNearDeathProtection" icon="ui_game_symbol_near_death_trauma" icon_color="0,255,0" remove_on_death="false" hidden="true">
Notice this at the end
remove_on_death="false"
My guess is that by default, all buffs are internally set to remove_on_death="true", so it doesn't need to be listed in the buff, since fewer buffs need to explicitly persist after death they decided to make removing buffs after death to be the normal default, then when they want it to persist they have to override it explicitly.
To test this, try adding this to some of the debuffs you want to test against, then get the debuff and die and see if it remains when you respawn