Aah yes, its a bug that we found that needs fixing in the next update. Add this CSS:
.wpsp-overlay.wpsp-ov-style-one .wp-show-posts-entry-summary {
opacity: 0.0;
-webkit-transform: translateY(1em);
transform: translateY(1em);
-webkit-transition: all 0.3s cubic-bezier(.33, .66, .66, 1);
transition: all 0.3s cubic-bezier(.33, .66, .66, 1);
-webkit-backface-visibility: hidden;
backface-visibility: hidden;
}