Hello everyone,
Having no answers, so I took the time to have a (long) look.
It seems that in the css file of sppagebuilder there are no more these css declarations (example taken from the themis demo site):
@media (min-width: 768px){
.sppb-col-sm-4 {
-ms-flex: 0 0 33.333333%;
flex: 0 0 33.333333%;
max-width: 33.333333%;
}
.sppb-col-sm-8 {
-ms-flex: 0 0 66.666667%;
flex: 0 0 66.666667%;
max-width: 66.666667%;
}
}
Ex : https://www.carillon-chambery.fr/medias
This lays out in 1/3(img) and 2/3 the info
By putting these declarations in the custom css file, everything works.
If it can help.