I think the simple explanation is that splits on the course were off. No idea why, but the race only had chip splits for 7.5k, 17.5k, 20k and finish.
Looking at the times for the top 10 men and women, something is obviously off, since the 10K between 7.5k and 17.5K was way too fast, and the 2.5k between 17.5k and 20k was way too slow (double the split for a 5K, and you can see something's off).
No idea if the 20K-21.0975K splits look okay. Some look a bit slow. I'd guess that Lel and Gharib covered the last 1097m in under 3:02, but it was a new course, so who knows how accurate things were.
Lugar no Escalão Lugar Geral Dorsal n.º Nome 7,5 Km 17,5 Km 20 Km Tempo de Chip Tempo Oficial País
1 27 50 GOUCHER,KARA 00:25:03 00:55:09 01:04:49 01:08:29 01:08:30 EUA
2 31 52 TIMBILILI,ALICE 00:25:13 00:55:38 01:05:22 01:08:58 01:09:00 QUE
3 32 61 KIPTOO,JANE 00:25:17 00:55:43 01:05:29 01:09:06 01:09:07 QUE
4 39 51 PROKOPCUKA,JELENA 00:25:18 00:56:37 01:06:21 01:09:57 01:09:58 LET
5 45 64 MALOT,LEAH 00:25:58 00:57:53 01:07:56 01:11:35 01:11:37 QUE
6 58 55 ROSA,MONICA 00:26:55 00:59:52 01:10:16 01:14:13 01:14:14 POR
7 65 53 WORKITU,AYANU 00:25:17 00:59:54 01:10:55 01:15:01 01:15:03 ETI
8 68 69 COSTA,FILOMENA 00:27:27 01:01:02 01:11:43 01:15:30 01:15:33 POR
9 73 63 IVANOVA,GALINA 00:27:28 01:01:02 01:11:47 01:15:47 01:15:50 RUS
1 1 3 LEL,MARTIN 00:21:50 00:48:29 00:56:53 00:59:54 00:59:56 QUE
2 2 2 GHARIB,JAOUAD 00:21:50 00:48:29 00:56:53 00:59:57 00:59:59 MAR
3 3 4 CHERUYOT,ROBERT 00:21:50 00:48:29 00:56:53 01:00:02 01:00:05 QUE
4 4 30 NGATUMY,GEDION 00:21:51 00:48:30 00:56:55 01:00:04 01:00:06 QUE
5 5 7 SHAURI,SAMUEL 00:21:51 00:48:43 00:57:19 01:00:31 01:00:33 TAN
6 6 14 MUTAI,EMMANUEL 00:21:51 00:48:46 00:57:26 01:00:44 01:00:45 QUE
7 7 1 WANJIRU,SAMUEL 00:21:52 00:48:44 00:57:59 01:01:23 01:01:25 QUE
8 8 31 KEMBOI,DAVID 00:22:08 00:50:14 00:59:23 01:02:51 01:02:53 QUE
9 9 34 RAMOS,JOSE 00:23:11 00:51:12 01:00:09 01:03:21 01:03:23 POR
10 10 5 CHELANGA,JOSHUA 00:22:52 00:51:12 01:00:09 01:03:23 01:03:25 QUE