Any thought on this?

A couple things,

Are you using xdebug on this server? It will trigger that error sometimes. You can increase the number in the php.ini xdebug seciton with xdebug.max_nesting_level=#

The other thing is on the Cache:put('...

Cache::put('box_banner', $ret, 60);

If this is the actual code, your cache key (box_banner) is not unique so your overwriting the cache ever time the function runs. Also you have no check if cache exists then load in there so all your doing is saving a cache every time.

Putting the cache check/load/save in the _box_banner function should work for caching the data. Especially if each of result of the function is different.