In #7 you mentioned that the error occur always on some big files. Can you please exclude them to test if BIT will correctly create a new snapshot without those and/or manually transfer those with:
rsync -rtDH --links --no-p --no-g --no-o --rsh="ssh -p 2222 " -v --chmod=Du+wx /path/to/big/file 'pi@192.168.0.254:"/mnt/backup/"'
In #7 you mentioned that the error occur always on some big files. Can you please exclude them to test if BIT will correctly create a new snapshot without those and/or manually transfer those with:
rsync -rtDH --links --no-p --no-g --no-o --rsh="ssh -p 2222 " -v --chmod=Du+wx /path/to/big/file 'pi@192. 168.0.254: "/mnt/backup/ "'