QGIS 3.16.0 "Execute as Batch Process" not working

[s6hebern]

For any processing algorithm:

1. Right-click --> Execute as Batch Process...
2. With the "+" and "-" buttons, lines should be added to or removed from the table. For me, nothing happens at all.

** Tried to reinstall, did not help **

QGIS and OS versions

QGIS version	3.16.0-Hannover	QGIS code revision	43b64b1
Compiled against Qt	5.11.2	Running against Qt	5.11.2
Compiled against GDAL/OGR	3.1.4	Running against GDAL/OGR	3.1.4
Compiled against GEOS	3.8.1-CAPI-1.13.3	Running against GEOS	3.8.1-CAPI-1.13.3
Compiled against SQLite	3.29.0	Running against SQLite	3.29.0
PostgreSQL Client Version	11.5	SpatiaLite Version	4.3.0
QWT Version	6.1.3	QScintilla2 Version	2.10.8
Compiled against PROJ	6.3.2	Running against PROJ	Rel. 6.3.2, May 1st, 2020
OS Version	Windows 10 (10.0)
Active python plugins	freehandEditing3; GlobeBuilder; Go2NextFeature3; latlontools; mmqgis; pluginbuilder3; pointsamplingtool; profiletool; QGIS3-getWKT; QuickWKT; quick_map_services; send2google_earth; Serval; SLD4raster; SplitPolygonShowingAreas; SpreadsheetLayers; valuetool; db_manager; MetaSearch; processing

[nicogodet]

Duplicate #39696 ?

[s6hebern]

True, did not search carefully enough. Apologies!