Mega Man 2 nonlooping animation bug

draw_player_sprite:
; Player sprites include Mega Man, his weapons,
; and "metaballs" when he explodes.
; Aside from a different location for graphics data and some
; special cases for Mega Man and bosses, this is largely the same
; as draw_enemy_sprites.
 0F:CDE4: A6 2B     LDX current_sprite_index
 0F:CDE6: BD 20 04  LDA sprite_flags,X
 0F:CDE9: 30 02     BMI +
; Sprite is inactive. Return.
 0F:CDEB: 18        CLC
 0F:CDEC: 60        RTS -----------------------------------------
+:
; Get main data pointer
 0F:CDED: BC 00 04  LDY sprite_ids[0],X
 0F:CDF0: B9 00 F9  LDA player_main_gfx_ptrs_lo,Y
 0F:CDF3: 85 08     STA $08
 0F:CDF5: B9 00 FA  LDA player_main_gfx_ptrs_hi,Y
 0F:CDF8: 85 09     STA $09
; Increment animation timer
 0F:CDFA: BD A0 06  LDA sprite_cel_nums[0],X
 0F:CDFD: 48        PHA
 0F:CDFE: FE 80 06  INC sprite_anim_timers[0],X
 0F:CE01: A0 01     LDY #$01
 0F:CE03: B1 08     LDA ($08),Y
 0F:CE05: DD 80 06  CMP sprite_anim_timers[0],X
 0F:CE08: B0 15     BCS +
; Timer expired, increment to next cel
 0F:CE0A: A9 00     LDA #$00
 0F:CE0C: 9D 80 06  STA sprite_anim_timers[0],X
 0F:CE0F: FE A0 06  INC sprite_cel_nums[0],X
; Check if we've passed the end of the animation
 0F:CE12: 88        DEY
 0F:CE13: B1 08     LDA ($08),Y
 0F:CE15: DD A0 06  CMP sprite_cel_nums[0],X
 0F:CE18: B0 05     BCS +
; End of animation. Loop it.
 0F:CE1A: A9 00     LDA #$00
 0F:CE1C: 9D A0 06  STA sprite_cel_nums[0],X
+:
; Start loading gfx data
; A = cel number
; Fetch cel ID from animation_data[cel_number + 2 ]
 0F:CE1F: 68        PLA
 0F:CE20: 18        CLC
 0F:CE21: 69 02     ADC #$02
 0F:CE23: A8        TAY
 0F:CE24: B1 08     LDA ($08),Y
 0F:CE26: D0 04     BNE +
; Cel 0 == end of nonlooping animation.
; Kill sprite.
;
; There's a bug here! If the flags bit 0 is set (which indicates
; the sprite collides with Mega Man), it will be shifted into the
; carry flag, giving an erroneous return value from this routine.
; This will make the main gfx routine return early.
 0F:CE28: 5E 20 04  LSR sprite_flags,X
 0F:CE2B: 60        RTS -----------------------------------------