Error Type: illegal_argument_exception

While trying to index a HUGE content website I’ve encountered the following repeated errors in the status report section:

“error”: {
“type”: “illegal_argument_exception”,
“reason”: “startOffset must be non-negative, and endOffset must be >= startOffset, and offsets must not go backwards startOffset=2949,endOffset=2953,lastStartOffset=2952 for field ‘post_content_filtered'”
}

It seems that it skipped indexing many posts or is not showing them. What could be the problem and how can I solve it?

I really appreciate any help you can provide 🙂