Getting floating point exceptions when using specific registers

Question

I have a below code when executed i see Floating point exception

.section .data
var1:
        .int 20
.section .text
.globl _start
_start:
        movl $var1, %edx
        movl (%edx), %eax
        movl $5, %ecx
        div %ecx
        movl %eax, %ebx
        movl $1, %eax
        int $0x80

when i execute the above code i get Floating point exception

../../bin/a49
Floating point exception (core dumped)

But in the above code if i change the register storing the address of var1 from edx to ecx, It works as expected

.section .data
var1:
        .int 20
.section .text
.globl _start
_start:
        movl $var1, %ecx
        movl (%ecx), %eax
        movl $5, %ecx
        div %ecx
        movl %eax, %ebx
        movl $1, %eax
        int $0x80

When i execute the above code i don't see the FPE.

$ ../../bin/a49
$ echo $?
4

I am unable to understand the above behaviour.