Per Adobe's announcement on May 20th:
"We’re introducing updated submission limits for Adobe Stock Contributors to help maintain the strength and quality of our growing collection. These updates support the continued success of both our Contributor community and customers alike. When you reach your weekly submission limit or the maximum amount of allowed content pending moderation, you will experience a temporary pause before you can submit additional content."
It is not unusual for review times to vary, and for different asset types to experience different review times.