Piglins currently have issues mounting into boats and minecarts. They will attempt to mount the entity but will not sit down. Instead they just stand on the mount.
MC-177652
Piglins do not mount boats or minecarts properly.
Resolved
Duplicate
0
Nolen Schmirler
(Unassigned)
Unconfirmed
(Unassigned)
20w14a
Retrieved
That is considered intentional; see MC-172255