@harizen posted a good link, as they have one common opponent in Shawn Porter. Maybe Shawn really knows that he lost to Ugas in their fight because it was really hard to score that fight. That's why he thinks that Ugas has a good chance, maybe slim but still he may find a way to beat Spence.
I'm sure the majority of us here thinks that Yordenis Ugas don't have a chance to win but Shawn Porter itself debunked that thinking as he already faced Ugas and he knows better than us here. Even he picks Spence Jr. to win the fight, he is sure that Ugas can hit an unexpected upset.
Ugas is now also in his post-prime and since the big break just comes late, he will do everything to have a good milestone a few years before entering the veteran age for boxers.