diff --git a/CHANGELOG.md b/CHANGELOG.md
index 23e1435e..64950e31 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -23,6 +23,7 @@
 - Dev: Mini refactor of Split. (#6148)
 - Dev: Conan will no longer generate a `CMakeUserPresets.json` file. (#6117)
 - Dev: Pass `--force-openssl` when installing from CMake in Qt 6.8+. (#6129)
+- Dev: Fixed `<build-tool> clean` not working correctly with generated sources. (#6154)
 
 ## 2.5.3
 
diff --git a/lib/twitch-eventsub-ws/cmake/GenerateJson.cmake b/lib/twitch-eventsub-ws/cmake/GenerateJson.cmake
index 4cfed82a..e1578f68 100644
--- a/lib/twitch-eventsub-ws/cmake/GenerateJson.cmake
+++ b/lib/twitch-eventsub-ws/cmake/GenerateJson.cmake
@@ -172,20 +172,18 @@ function(generate_json_impls)
 
     foreach(_header ${arg_HEADERS})
         # keep in sync with generate.py
-        string(REGEX REPLACE \.hpp$ .inc _def_path "${_header}")
         string(REGEX REPLACE \.hpp$ .cpp _source_path "${_header}")
         string(REGEX REPLACE \.hpp$ .timestamp _timestamp_path "${_header}")
         string(REGEX REPLACE include[/\\]twitch-eventsub-ws[/\\] src/generated/ _source_path "${_source_path}")
 
         cmake_path(ABSOLUTE_PATH _timestamp_path BASE_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}/eventsub-deps")
         cmake_path(ABSOLUTE_PATH _header BASE_DIRECTORY "${arg_BASE_DIRECTORY}")
-        cmake_path(ABSOLUTE_PATH _def_path BASE_DIRECTORY "${arg_BASE_DIRECTORY}")
         cmake_path(ABSOLUTE_PATH _source_path BASE_DIRECTORY "${arg_BASE_DIRECTORY}")
         list(APPEND _all_sources "${_source_path}")
 
         if(_generation_supported)
             add_custom_command(
-                OUTPUT "${_timestamp_path}" "${_source_path}" "${_def_path}"
+                OUTPUT "${_timestamp_path}" "${_source_path}"
                 DEPENDS ${_gen_deps} "${_header}"
                 COMMENT "Generating implementation for ${_header}"
                 COMMAND "${_python3_path}" "${_gen_script}" "${_header}" --includes "${_inc_dirs}" --timestamp "${_timestamp_path}"