When Drupal processes each migration, it displays information such as the following:

Processed 36 (36 created, 0 updated, 0 failed, 0 ignored) in 28.1 sec (77/min) - continuing with 'phpbb_DOMAIN_forum_Post'
Processed 29 (29 created, 0 updated, 0 failed, 0 ignored) in 27.1 sec (64/min) - continuing with 'phpbb_DOMAIN_forum_Post'
Processed 32 (32 created, 0 updated, 0 failed, 0 ignored) in 27.1 sec (71/min) - continuing with 'phpbb_DOMAIN_forum_Post'
...

This seems to show that the first iteration imported the first 36 records, the second iteration imported the next 29 records, the third iteration imported the next 32 records, and so on. So 97 records will have been imported so far. And the migration will continue until they've all be processed.

However, there seems to be an issue with the import of avatars.

When avatars are imported, similar information is displayed:

Processed 36 (36 created, 0 updated, 0 failed, 0 ignored) in 28.1 sec (77/min) - continuing with 'phpbb_DOMAIN_forum_Avatar'
Processed 29 (29 created, 0 updated, 0 failed, 0 ignored) in 27.1 sec (64/min) - continuing with 'phpbb_DOMAIN_forum_Avatar'
Processed 32 (32 created, 0 updated, 0 failed, 0 ignored) in 27.1 sec (71/min) - continuing with 'phpbb_DOMAIN_forum_Avatar'
...

However, it seem here that the second iteration imported the first 29 records again, and the third iteration imported the first 32 records again. So only 36 will have been imported. And the migration continues indefinitely (unless it can complete the entire import within one iteration).