Attempting to trigger "Optimize Imports" in the following file triggers a StackOverflowError and IntelliProcessor seems to be the culprit. The weird thing is the project isn't even using Preprocessor.
https://github.com/lunaynx/Skyblocker/blob/ce60fef533e82ea3ec8118fd68936d8dad5c5fda/src/main/java/de/hysky/skyblocker/mixins/CactusBlockMixin.java
stacktrace.txt