I've created an extremely challenging regex problem that incorporates multiple pattern types requiring advanced techniques to match correctly. The text contains a system audit log with valid and invalid identifiers, where only specific valid formats should be matched. This challenge requires:

1. Matching multiple different format types (user IDs and export IDs)
2. Distinguishing between valid and invalid patterns with subtle differences
3. Handling mixed formats with different prefixes, delimit... (truncated)