[Build Error] "Package registered twice" error when adding custom packages (exigo / luci-app-exigo)

Describe the bug

I am encountering a "Package registered twice" build error while compiling OpenWrt for my target device. I have added two custom packages (exigo and luci-app-exigo) and the build system seems to have cached a duplicate registration, even after attempting several cleanup commands.
Environment
Target Device: [Es: IPQ5018 / Xunison Exigo Hub D50-5G]
Host OS: [Es: Ubuntu 22.04 / Debian 12]
OpenWrt Source: [Es: Main branch / ImmortalWrt 23.05]
Steps to Reproduce
Created directory package/exigo and package/luci-app-exigo.
Added corresponding Makefile files to both directories.
Ran make defconfig and started compilation with make -j$(nproc).
The build fails with the error: Package registered twice.
What I've already tried
I have attempted to clear the build cache to resolve potential metadata conflicts, but the error persists:

rm -rf tmp/

make package/cleanup

make dirclean

make defconfig

Verified that PKG_NAME and define Package/... are unique and distinct in both Makefile files.

Additional Context
I have checked the OpenWrt forum and existing issues on GitHub, confirming this is likely a stale metadata issue, but standard cleanup procedures are not resolving the conflict in my build environment.

OpenWrt version

VERSION_NUMBER:=23.05.0

OpenWrt release

VERSION_CODE:=$(shell git describe --tags 2>/dev/null || echo "r0-unknown")

OpenWrt target/subtarget

grep "CONFIG_TARGET_BOARD" .config e grep "CONFIG_TARGET_SUBTARGET" .config

Device

xunison_exigo-hub-d50-5g

Image kind

Self-built image

Steps to reproduce

No response

Actual behaviour

No response

Expected behaviour

No response

Additional info

No response

Diffconfig

Terms

• I am reporting an issue for OpenWrt, not an unsupported fork.

Inspect the Makefiles under package/exigo and package/luci-app-exigo, then rerun the build after reviewing the full duplicate-registration error. Compare each PKG_NAME and define Package/... declaration and document which registration is duplicated; the issue lacks the actual error output and Makefile contents needed to confirm the cause.