Adventure map, boat shadow is not rendered fully

[Branikolog]

Preliminary checks

• [X] I've checked that there aren't other open issues on the same topic.
• [X] I've checked that this issue is reproducible on the latest snapshot build.

Platform

Windows

Describe the bug

https://github.com/ihhub/fheroes2/assets/55348946/9ac703ba-30e9-461b-84e3-62cf12d398bc

The shadow of the boat nearby is rendered partially.

Save file

boat shadow.zip

Additional info

No response

[ihhub]

Relates to #5716 .

[Districh-ru]

It seems that this map was a result of incorrect Summon Boat or other action resulting in changed the river delta's layer type from Terrain layer to Object layer:

--------- Level 1 --------
UID             : 1605
ICN object type : 41 (OBJNMUL2.ICN)
image index     : 8
layer type      : 0 - Object layer
is shadow       : no

I've started a new game on the Seven Lakes map, tried to summon a boat and could not reproduce this bug:

https://github.com/user-attachments/assets/7758c5c2-3272-4b22-91d6-5c7cc9083acd

Possibly it is already fixed...