Wrong output of "Surface to polygon" algorithm

[DelazJ]

What is the bug or the crash?

I'm testing the abovementioned algorithm (#58941) in order to document it, and what I get is not what I was expecting, There should be a hole in the exported polygon while there isn't.

Steps to reproduce the issue

The mesh dataset is available at Madagascar wind
Running the "Surface to polygon" alg on it, this is what I get:

The help text states:

This algorithm exports a polygon file containing mesh layer boundary. It may contain holes and it may be a multi-part polygon.

• Shouldn't there be a hole where "Madagascar" island is?
• I first read this as it would merge the consecutive faces and output a polygon representing the actual limits of the mesh. But if it outputs the bounding box of the mesh layer, in what context does it output a multi-part feature?

Versions

Version de QGIS	3.41.0-Master
Révision du code	0cd5ccd42a
Bibliothèques
Version de Qt	5.15.13
Version de Python	3.12.9
Version de GDAL/OGR	3.11.0dev-d748f651f4
Version de Proj	9.5.1
Version de la base de données du registre EPSG	v11.022 (2024-11-05)
Version de GEOS	3.13.0-CAPI-1.19.0
Version de SQLite	3.46.1
Version de PDAL	2.8.3
Version du client PostgreSQL	unknown
Version de SpatiaLite	5.1.0
Version de QWT	6.3.0
Version de QScintilla2	2.14.1
Version de l'OS	Windows 10 Version 2009
Cette copie de QGIS dispose d'une sortie de débogage.
Extensions Python actives
lizmap	4.4.6
plugin_reloader	0.17
Qgis2threejs	2.8
db_manager	0.1.20
grassprovider	2.12.99
MetaSearch	0.3.6
processing	2.12.99
MapsPrinter	1.0

Supported QGIS version

• I'm running a supported QGIS version according to the roadmap.

New profile

• I tried with a new QGIS profile

Additional context

No response