different results for ST_Relate with 3 parameters compared to those for ST_Relate with 2 parameters

[Antonio Valanzano]

I am following the "Introduction to PostGIS " tutorial  at
https://postgis.net/workshops/postgis-intro/
and for chapter 26 "Dimensionally Extended 9-Intersection Model"  I am
trying to replicate the examples.

If I use the two different versions of ST_Relate I do not obtain the same
result

SELECT
  d.id,
  ST_Relate(d.geom, l.geom) as patternMatrix
FROM docks as d, lakes as l
WHERE ST_Relate(d.geom, l.geom, '1FF00F212') = true;
-- 1 row
"id" "patternmatrix"
1    "1FF00F212"



SELECT
  d.id,
  ST_Relate(d.geom, l.geom) as patternMatrix
FROM docks as d, lakes as l
WHERE ST_Relate(d.geom, l.geom) = '1FF00F212';
-- 2 rows
"id" "patternmatrix"
1    "1FF00F212"
2    "1FF00F212"

Could someone give me an explanation of such a difference ?