Common system mistakes?

Hi everyone,
I've been deeply interested lately looking into businesses (mainly service sector) have transitioned from first owner through growth and are looking to get acquired due to lack of skills / systems to handle their new size. It seems pretty obvious the skills to get off the ground and the skills to manage a medium enterprise don't really overlap.

Has anyone here that have been getting picking up high-growth / post-growth businesses and digging into their operations noticed any common systemic issues and have any experience or observations to share? I've mostly got a very Australian focus so I'd love to hear from the broader global community.