[Bug] PPA upgrade fails: openlist.service.dpkg-new No such file or directory

[gucong3000]

Environment:
OS: Ubuntu 20.04 (Ubuntu Touch / phablet)
Architecture: arm64
PPA Source: ppa:openlist/server
Failing Version: 4.1.10-1ubuntu1~20.04.1 (Upgrading from 4.1.10-1)
Description:
Every time I attempt to upgrade openlist via the official PPA, the process fails during the unpacking phase. The core issue is that dpkg cannot create/open /usr/lib/systemd/system/openlist.service.dpkg-new, leading to a cascade of failures in the postinst script because the service file "does not exist."
Error Logs:

(Reading database ... 98021 files and directories currently installed.)
Preparing to unpack .../openlist_4.1.10-1ubuntu1~20.04.1_arm64.deb ...
Unpacking openlist (4.1.10-1ubuntu1~20.04.1) over (4.1.10-1) ...
dpkg: error processing archive /var/cache/apt/archives/openlist_4.1.10-1ubuntu1~20.04.1_arm64.deb (--unpack):
 unable to open '/usr/lib/systemd/system/openlist.service.dpkg-new': No such file or directory
usermod: no changes
Failed to enable unit: Unit file openlist.service does not exist.
dpkg: error while cleaning up:
 installed openlist package post-installation script subprocess returned error exit status 1

My Current Workaround:
I have to manually intervene by extracting the service file from a known working .deb and creating the expected .dpkg-new placeholder:
Extract openlist.service from a manual download.

sudo cp ... /usr/lib/systemd/system/openlist.service
sudo touch /usr/lib/systemd/system/openlist.service.dpkg-new
sudo apt install -f

However, the next apt upgrade triggers the same error.