Log of failed backup: not all chunks?

I’m running some tests, and I got this result for a check:

snap | rev |                          | files |  bytes | chunks |  bytes | uniq |   bytes |  new |   bytes |
test |   1 | @ 2018-05-16 10:36 -hash |     1 | 2,048M |   2052 | 2,056M |   40 | 39,179K | 2052 |  2,056M |
test |   2 | @ 2018-05-16 22:36       |     1 | 2,048M |   2052 | 2,056M |   28 | 26,842K |   40 | 39,179K |
test |   3 | @ 2018-05-31 01:56       |     1 | 2,048M |   2052 | 2,056M |   17 | 15,533K |   58 | 57,685K |
test |   4 | @ 2018-06-01 12:26       |     1 | 2,048M |   2052 | 2,056M |    1 |    111K |   28 | 26,842K |
test |   5 | @ 2018-06-03 20:44       |     1 | 2,048M |   2051 | 2,056M |    0 |       0 |    2 |    112K |
test |   6 | @ 2018-06-04 20:03       |     1 | 2,048M |   2051 | 2,056M |    0 |       0 |    0 |       0 |
test |   7 | @ 2018-06-05 20:04       |     1 | 2,048M |   2051 | 2,056M |    0 |       0 |    0 |       0 |
test |   8 | @ 2018-06-06 20:22       |     1 | 2,048M |   2051 | 2,056M |    0 |       0 |    0 |       0 |
test |   9 | @ 2018-06-07 20:18       |     1 | 2,048M |   2051 | 2,056M |    0 |       0 |    0 |       0 |
test |  10 | @ 2018-06-08 15:38       |       |        |      3 |    318 |    3 |     318 |    3 |     318 |
test |  11 | @ 2018-06-08 15:39       |     1 | 2,048M |   2052 | 2,056M |    1 |    111K |   88 | 88,527K |
test |  12 | @ 2018-06-09 22:12       |     1 | 2,048M |   2051 | 2,056M |    0 |       0 |    1 |    111K |
test |  13 | @ 2018-06-10 20:04       |     1 | 2,048M |   2051 | 2,056M |    0 |       0 |    0 |       0 |
test |  14 | @ 2018-06-11 20:13       |     1 | 2,048M |   2052 | 2,056M |   49 | 48,432K |   49 | 48,432K |

I know what happened in revision 10. This is a Veracryt volume, which was in use, and was not backed up:

2018-06-08 15:38:23.120 WARN OPEN_FAILURE Failed to open file for reading: open [file]
2018-06-08 15:38:23.368 WARN SKIP_FILE File [file] cannot be opened
...
2018-06-08 15:38:23.368 INFO BACKUP_END Backup for [rep] at revision 10 completed
2018-06-08 15:38:23.369 INFO BACKUP_STATS Files: 0 total, 0 bytes; 0 new, 0 bytes
2018-06-08 15:38:23.369 INFO BACKUP_STATS File chunks: 0 total, 0 bytes; 0 new, 0 bytes, 0 bytes uploaded
2018-06-08 15:38:23.369 INFO BACKUP_STATS Metadata chunks: 3 total, 75 bytes; 3 new, 75 bytes, 318 bytes uploaded
2018-06-08 15:38:23.369 INFO BACKUP_STATS All chunks: 3 total, 75 bytes; 3 new, 75 bytes, 318 bytes uploaded
2018-06-08 15:38:23.369 INFO BACKUP_STATS Total running time: 00:00:01
2018-06-08 15:38:23.369 WARN BACKUP_SKIPPED 1 file was not included due to access errors

The next job (revision 11, few moments later) ran without errors:

2018-06-08 15:39:34.227 INFO BACKUP_END Backup for [rep] at revision 11 completed
2018-06-08 15:39:34.227 INFO BACKUP_STATS Files: 1 total, 2,048M bytes; 1 new, 2,048M bytes
2018-06-08 15:39:34.227 INFO BACKUP_STATS File chunks: 2049 total, 2,048M bytes; 86 new, 88,064K bytes, 88,415K bytes uploaded
2018-06-08 15:39:34.227 INFO BACKUP_STATS Metadata chunks: 3 total, 150K bytes; 2 new, 134K bytes, 112K bytes uploaded
2018-06-08 15:39:34.227 INFO BACKUP_STATS All chunks: 2052 total, 2,048M bytes; 88 new, 88,198K bytes, 88,527K bytes uploaded
2018-06-08 15:39:34.227 INFO BACKUP_STATS Total running time: 00:00:37

My question is: why did the execution log with error show All chunks: 3 total and not All chunks: 2052 total?