WHY IS THERE A SPACE AND AND A ! at the beggining of my last printed string from the loop?

.MODEL SMALL

 .STACK 100H

 .DATA?
    STRING1  DB  "The Computer Programmers Motto:",0
    STRING2  DB  "When in doubt,", 0
    STRING3  DB  "mumble!", 0
    STRING4  DB   128 dup(?)
    STRING5  DB   128 dup(?)

    lstring EQU $ - string1



    .CODE


START:
    MOV AX, @DATA               ;   set up addressability of data
    MOV DS,AX                   ;
    MOV     SI,0                ;   index register
    MOV     CX,LSTRING      ;   loop counter number of bytes to move
L1:
    MOV     AL,STRING1[SI]      ;   get char from source
    LOOP    L1                  ;   repeat for entire string


    mov ax, 4000h               ;   set up service to display string
    mov bx, 1                   ;   to monitor
    mov cx, 31                  ;   number of bytes to print
    mov dx,OFFSET STRING1       ;   where to find it
    int 21h                     ;   do it

    MOV AH, 2                    ;  carriage return
    MOV DL, 0DH
    INT 21H

    MOV DL, 0AH                  ;  line feed
    INT 21H

L2:
    MOV     AL,STRING2[SI]      ;   get char from source
    LOOP    L2                  ;   repeat for entire string


    mov ax, 4000h               ;   set up service to display string
    mov bx, 1                   ;   to monitor
    mov cx, 14                  ;   number of bytes to print
    mov dx,OFFSET STRING2       ;   where to find it
    int 21h                     ;   do it

    MOV AH, 2                    ;  carriage return
    MOV DL, 0DH
    INT 21H

    MOV DL, 0AH                  ;  line feed
   INT 21H

L3:
    MOV     AL,STRING3[SI]      ;   get char from source
    LOOP    L3                  ;   repeat for entire string


    mov ax, 4000h               ;   set up service to display string
    mov bx, 1                   ;   to monitor
    mov cx, 7                   ;   number of bytes to print
    mov dx,OFFSET STRING3       ;   where to find it
    int 21h                     ;   do it

    MOV AH, 2                    ;  carriage return
    MOV DL, 0DH
    INT 21H

    MOV DL, 0AH                  ;  line feed
    INT 21H

L4:
    MOV     AL,STRING1[SI]      ;   get char from source
    MOV     STRING4[DI],AL      ;   store in the target
    INC     SI                  ;   move to next character
    LOOP    L4                  ;   repeat for entire string


    mov ax, 4000h               ;   set up service to display string
    mov bx, 1                   ;   to monitor
    mov cx, lstring             ;   number of bytes to print
    mov al,OFFSET STRING4       ;   where to find it
    int 21h                     ;   do it

    MOV AH, 2                    ;  carriage return
    MOV DL, 0DH
    INT 21H

    MOV DL, 0AH                  ;  line feed
    INT 21H
    ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;




    mov ah,4ch                  ;   set up service to return to OS
    int 21h

    END start