Even when there are lots of stack samples there may only be a few memory samples

<img width="1207" height="507" alt="Image" src="https://github.com/user-attachments/assets/5048528f-6789-494f-901f-5bd96056330d" />

In this case the profile had 2,066,272 samples @ ~10ms (which is in itself another bug https://github.com/catalyst/moodle-tool_excimer/issues/403)