It uses "STAMPS_DIR=/another/dir bitbake -S none <recipe>" to generate new stamps and compare to old stamps to get the data, but now once STAMPS_DIR is changed, the old stamps and work dir will be removed, so that it doesn't work any more.

We may look for other ways to fix it in YP 2.3, for example, add handler or use the handler printdiff for -S to fix the problem.

And comments from RP:
I don't believe that script always worked as it should and I really want to see usecases and better tests of what its showing rather than just blindly reimplmenting it in runqueue.py