the character can not carry the corpses of some monsters
the character can not carry the corpses of some monsters, such as wild boars, flesh, snork.
Why do you believe that's a bug?
Dragging is supported for a character model if it's listed under [ph_capture_visuals] in gamedata\configs\system.ltx. The vanilla mutant model list is:
;monsters\controller\controller_1
;monsters\controller\controller_2
;monsters\controller\controller_3
;monsters\controller\controller_4
;monsters\controller\controller_dead
;monsters\crow\crow
monsters\dog\dog
monsters\dog\dog_bulterier
monsters\dog\dog_bulterier_dead
monsters\dog\dog_dead
monsters\dog\dog_red
monsters\dog\dog_red_dead
monsters\dog\dog_white
monsters\dog\dog_white_dead
;monsters\flesh\flesh
;monsters\flesh\flesh_dead
;monsters\flesh\flesh_strong
monsters\krovosos\krovosos
monsters\krovosos\krovosos_dead
monsters\krovosos\krovosos_strong
monsters\krovosos\krovosos_strong_xray
monsters\krovosos\krovosos_xray
;monsters\mutant_boar\mutant_boar
;monsters\mutant_boar\mutant_boar_dead
;monsters\mutant_boar\mutant_boar_strong
;monsters\poltergeist\poltergeist
;monsters\poltergeist\poltergeist_dead
;monsters\poltergeist\poltergeist_strong
monsters\pseudodog\pseudodog
monsters\pseudodog\pseudodog_dead
monsters\pseudodog\pseudodog_grey
monsters\pseudodog\pseudodog_grey_dead
;monsters\rat\rat_1
;monsters\snork\snork
;monsters\snork\snork_dead
;monsters\tushkano\tushkano
;monsters\tushkano\tushkano_dead
The entries for all mutants except dogs and bloodsuckers have been commented out by GSC.
We might speculate that some mutants are too large/heavy for Scar to lift - but then why would crows (ph_mass = 1) and tushkanos (ph_mass = 20) not be draggable when bloodsuckers (ph_mass = 150) are? Going by weight alone, even snorks (ph_mass = 90), controllers (ph_mass = 90), and poltergeists (ph_mass = 80) should be draggable since they weigh less than bloodsuckers. Not sure what GSC's intention was.
and poltergeists
Poltergeists only leave a body after death in SoC.