EXTINF numbers in HLS manifest chunklist sometimes sum to more than audio file duration

Wowza Streaming Engine
1

E.g., the chunklist in this playlist sums to 47:53.443, while the actual file (mp3, 66MB) is only 47:49.16.

Meanwhile, the chunklist in this playlist correctly sums to 54:03.168 (compare file, also mp3, 66MB).

What’s causing the discrepancy?