actual tested with 7.3.4 and dev (incl. date), drupal 7.22
activated cach in calender view for all, incl. Block

Using a calendar block in a region, ther the prev and next Links are not working. No change of the month is happening.

A Link Example for the Block View, actual staying on August:
no change happens

In the Month View the Link of the prev Link si like this

The Problem only occurs when caching ist active set.
By the way ical is not working too while caching. But caching is neccessary because the performance is to bad.