I was able to replicate your problem by logging in as you. I don't know why it is an issue that only pertains to some users, but will investigate further as to whats causing it.
Thanks.

 

Thanks Adrian...

 

update....

i fiddled around on my forum, replicated the signature rules of this forum and was able to replicate the same error..

the Message Editor Interface is causing this problem.

if you select WYSIWYG as the editor and you have alot of rules applied, you'll get the same issue i'm getting now. so when i made it less restrictive, i was able to update my signature..

the same thing i've done here.. since i'm unable to change the forum rules, i changed my message editor to Basic Editor and was able to update my signature.

there you go IB, a solution to look into.

 

Sorry - we worked out what the issue was yesterday afternoon, and it should be good now.