When I invoke the code completion panel, in the archived file, the "IntellijIdeaRulezzz" pattern appears in the cursor location. For example, when I type "Sy" in the following figure, the archival mechanism records "SyIntellijIdeaRulezzz".

This is because the IntelliJ Platform inserts a dummy identifier into the text editor for some unknown implementation reasons when invoking auto-completion. The best way to solve it is to filter out them as noise when post-processing the data. See the link for more details.

Thanks to the research team led by Prof. Dr. Romain Robbes for pointing out this issue.