99.99% of sessions only consist of one pageview, see below. But per https://meta.wikimedia.org/wiki/Schema_talk:RelatedArticles , the session token is meant to persist for the entire browser session beyond one pageview. (As also noted there and at T157307#3282646, it can happen that the token gets lost in case local storage is full, but that's unlikely to be the case in 99.99% of views.)
```lang=sql,lines=5
SELECT pages, COUNT(*) AS sessions FROM (
SELECT COUNT(DISTINCT event_pageId) AS pages
FROM log.RelatedArticles_16352530
WHERE wiki = 'enwiki' and event_skin = 'minerva-stable'
AND LEFT(timestamp, 6) = '201704'
GROUP BY event_userSessionToken) AS pages_per_session
GROUP BY pages
ORDER BY pages
pages sessions
1 5269122
2 93
3 54
4 28
5 23
6 14
7 9
8 8
9 12
10 7
11 2
12 3
13 5
14 1
15 3
17 3
18 3
19 3
20 1
24 2
26 1
30 2
33 1
35 1
39 1
40 1
41 2
45 1
48 1
49 1
52 1
54 1
57 1
59 1
61 1
62 1
63 1
64 2
67 1
68 2
69 1
75 1
80 1
81 1
84 1
152 1
158 1
```