I think barnacle may be referring to Chambers, not BRB.
Just completed it with a slight sense of unease because, although I’ve got all the missing letters in the down clues and the answer which enables me to interpret the first two and produce an intelligible clue, I haven’t actually solved that clue and got the 2,5,5 description of the ‘event’ (although I know what it is and when it occurred). But that doesn’t seem to matter. Have I missed something?
Other than that an enjoyable challenge. The final twist to produce what I assume is the correct word in the starred cells had me flummoxed for a while.