This is the result of a 2 things combined, a slow or inconsistent internet connection, and the apps small video buffer size. Videos only buffer so far ahead and when the buffer size is small like the crunchy rolls app is, and your internet is spotty then it can't buffer in time. When you have a large buffer.

How do I fix Crunchyroll buffering?

Solving Crunchyroll Mobile and Console Buffering

On any non-desktop platform, the fastest method to solve a choppy playback or buffering problem is to close out of the Crunchyroll app entirely, reset your device's internet connection and then restart Crunchyroll.

Why is Crunchyroll being so slow?

Whether you're watching Crunchyroll or Hulu, the root cause of the slow playback speeds is almost always the same – your internet connection speed. ... Crunchyroll's streaming service still uses Adobe Flash Player, which is somewhat “ancient” technology by today's standards.