certain Internet address do not properly show up c

I was responding to a comment in my blog and I need to place a couple of links in my comment. One link was a php file with the ending
…..index.php?p=124
This address showed up correctly. However, I went to copy and paste a link to an address ending
…..display_word.html?ID=1857
and the link copied directly into my comments box, but when I clicked my submit button and saw the comment the “=” was missing and I saw a
…..display_word.html?ID1857 (less the ‘=’ mark)
I clicked on the link in the comment to access the page and the link appeared in my browser less the ‘=’ mark. I went to edit the comment in the admin station to see if the ‘=’ sign was missing and the ‘=’ sign was present in the comments.
Is this a ‘bug’ in WordPress involving an .html file or possibly a capital letter before the ‘=’ mark or something else. I thought this was very wierd. Any comments?