Off Site Image Link Broken When Smilie Code Is Set As jpg

Off site images linked on a forum using the IMG code are broken if an administrator of a forum sets a smilie with the smilie code as jpg

If smilie code is set as jpg - see picture attachment 1

Then any links posted using the IMG BB code that has the extension jpg are broken, they have the jpg extension stripped from the URL - see picture attachment 2 and note that the jpg file extension is missing form the end of the URL.

This occurs even if an image URL with the extension jpg is posted without the IMG BB code wrap - the jpg extension is stripped and in its place the smilie will appear resulting in a broken URL

Obviously this only happens if a smilie code is set at jpg and the issue is resolved by changing the smile code to something other than jpg - However this does not retrospectively fix any links that were posted prior to the change and these would need to be fixed manually.

Is this a bug? I am not sure but was advised to report it as such