What does the grey exclamation mark mean?

Grey exclamation marks indicate that a related NZ Standard has been updated by Smartspec and needs your input to update the reference to that Standard in your specification. There's a more detailed explanation on this process here

Red exclamation marks are to alert you that an entire specification has been updated. You can then choose to add the new version of this specification or keep the old version. There's a more detailed explanation on this process here