When a :port is included in the CacheKeyBaseURL the ":" is lost from the actual cache key value. This doesn't harm apache by itself, the real problem arise if some external program which "knows" about the cache keys structure is used to modify the cache.
When CacheKeyBaseURL is not use, the ":" is kept.
So, be consistent when building the key and keep the ":" in all cases.
PR 53915 [Rein Tollevik <rein basefarm.no>]
+ merge 2 lines of a comment to have it more compact