Just happened to me too! I hate it! I do hope it's not deliberate. I feel MN looong titles is part of the humour...it contributes to the particular brand of funny that IS Mumsnet.
I bet it's something to do with Google...I BET they want the titles to be more googleable.
Good title for Google = "Why won't my husband have sex with me?"
Not good for Google = "My twunty DH won't shag me any more, should I LTB?"