Yes, it's not issue from SPPB itself, but from Casiopea Custom CSS file.
.icone-liquid-glass button[aria-expanded="true"] .sppb-accordion-image {
content: url("/files/2026/04/03/minus.svg");
}
It's loaded by file: media/templates/site/cassiopeia_extended/css/user.css
And it force (-) as first default icon
If you cannot edit that (user.css) file (but you should) then use below Custom CSS line in Page Settings > Page CSS
.icone-liquid-glass button[aria-expanded="true"] .sppb-accordion-image {
content: none;
}
simple conflict