`seg_id0` is duplicated for the root segment for big files when multiple files are loaded

[yruslan]

Describe the bug

seg_id0 should never be duplicated for the root segment.

However, when loading big files, we see duplications.

Code snippet that caused the issue

Maybe this is happening only when record length field is used:

  .option("record_format", "F")
  .option("record_length_field", "REC_LENGTH + 17")
  .option("segment_field", "SEGMENT-ID")

Expected behavior

seg_id0 should never be duplicated for the root segment.

Context

• Cobrix version: 2.7.5
• Spark version: 3.3.4
• Scala version: 2.12
• Operating system: --

Copybook (if possible)

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Attach a small data file that can help reproduce the issue, if possible.