Why does sed delete the wrong range of lines

Im trying to write a script that deletes a certain range of lines using the sed command. I first printed out the lines.

    sed -n '482,486p' original.json
                {
                    "vlans": "ALL",
                    "hostname": "hostname",
                    "interface": "interface"
                },

After confirming that those are the lines I executed the following code

sed '482,486d' original.json > new.json

When I ran the diff command I got the following results

diff original.json new.json
484,488d483
<                     "hostname": "hostname",
<                     "interface": "interface"
<                 },
<                 {
<                     "vlans": "ALL",

My question is why was the range of lines from 484-448 deleted when I specified lines 482-486 to be deleted and how do I fix it. Any help would be appreciated

Solution

You haven't given us enough information to reproduce the error, but I'll go out on a limb.

My guess is that lines 487 and 488 of the original file are

{
    "vlans": "ALL",

So if we put the original and the new side by side, it looks like this:

481 ...     481 ...
482 {       487 {
483 vlans   488 vlans
484 host    489 ...
485 int
486 }
487 {
488 vlans
489 ...

So lines 482-486 were excised from original, but diff sees everything matching up through line 483, then five lines 484-488 in original not appearing in new, and then all the rest matching.