Lacking Leadership. Leadership is part production and part collaboration with the team. Leadership more often than not makes decisions and collaborates only with upper management. If you're looking for deep team collaboration and mentorship to grow your skills, look elsewhere. It was a great project to work on, but if you're not "invited" into the in-crowd of Leadership, your skills are going to atrophy.
SPP is a smaller studio under Sony. Expect to perform the job of 1.5-2.5 people for long periods of time. Burnout is a perpetual slow poison here.
If you join SPP be aware that they are an engineering-focused studio and their tools reflect that. If you're expecting a pretty engine with standard tools, don't. You'll be taking twice the time to complete something because almost all of SPP's tools are still text-based and very manual, even a lot of the art tools. This is not Unity/Unreal where you have visual editors for things. SPP is growing in better tools, but it does add resistance to productivity. To SPPs credit, some of their tool approaches are far favorable because of the versatility of how to go about creating something.