Data Integration/Management Error Handling

We have a flat file load which loads into our EPBCS application into a custom BSO cube.

Our load failed because members in our Project dimension did not exist, but existed in the file.

But the error log only said:

"java.lang.RuntimeException: Not all dimensions were specified."

I have seen this happen before, but can never understand why? How come sometimes we have an error 3303 indicating a missing member, but sometimes it doesn't show up at all in the log, and you just get the above message.

In fact, just iterations of the same load earlier, we got an error that a different dimension's member did not exist: