[LON-CAPA-users] mystery string response

[Ray Batchelor]

I have just one instance in which a student submitted a stringresponse
answer which, according to PGRD and the "Previous tries" display, is
identical to the correct answer, but which was nonetheless graded
"Incorrect".  Re-submission of the unchanged, redisplayed string was
graded "Correct".

Is it possible that the original response contained a character which
became stripped from the redisplayed string?   Or is there some other
likely explanation?

-- 
Ray