When I end a sequence with "Back Away", that sequence is never
successfully proofread even though no error is reported.
"Back Away" is not a valid last call. In order for a sequence to be proofread, the sequence must end with "Allemande Left",
"Right & Left Grand", or "Home" (or "You're Home").
To solve your problem, just add a final line with the word(s)
"Home" or "You're Home!"