I thought the problem might have had something to do with GeneratePress settings or the CSS I was using. I found out the problem was happening because long words (or words connected with   non-breaking space) will increase the size of a flex box beyond the specified width.
I was able to solve the problem by adding this css.
.wp-show-posts-columns .wp-show-posts-single:not(.wp-show-posts-masonry-block) {
word-break: break-word;
}
I will open a support topic in the plugin page for the other question about showing the updated date.