Sorted. It was the BP Templates Pack plugin conflicting with the new Suffusion theme. I have since disabled this plugin and installed the new Suffusion BP Pack instead.
@hnla – Thank you for highlighting that fact the “?” is supposed to be there – I’ve looked at other bp installs and I see what you mean about the clickable reveal @mention guidance text. I must have just not noticed it before it stopped working.
I’ve just this minute upgraded my Suffusion theme from 3.6.8 to 3.6.9 and this hasn’t made any difference. I had initially upgraded from 3.6.6 couple of weeks ago – this may have been when this issue first occurred.
I’ll highlight this on the Suffusion support forum to see if it is theme related. I’ll let you know.
Thanks.