Add ignore policy not working

Hello,

I’m trying to exclude directory using kopia policy command (instead of .kopiaignore), but it doesn’t seem to work as expected.
Here’s my steps:

Environment:

$ kopia --version
0.18.2 build: c70f1a1c1164ee8676f85f9a1cea6de0a782a3ae from: kopia/kopia

$ lsb_release -cri
No LSB modules are available.
Distributor ID: Ubuntu
Release:        24.04
Codename:       noble

tree output of source directory:

 static-binaries
 ├── arm
 ├── mips64
 ├── mipsel
 ├── README
 └── x86_64

 5 directories, 1 file

Using the kopia policy set command to exclude the mipsel directory, and kopia snapshot estimate to verify the exclusion result, the output is as follows:

kopia policy set /home/user/static-binaries --add-ignore '/mipsel'
kopia snapshot estimate /home/user/static-binaries

Snapshot includes 115 file(s), total size 172.3 MB
   10 MB ...100 MB:       1 files, total size 40.8 MB
   1 MB  ... 10 MB:      45 files, total size 105.9 MB
   100 KB...  1 MB:      33 files, total size 25.5 MB
   1 KB  ... 10 KB:      16 files, total size 58.4 KB
   0 B   ...  1 KB:      20 files, total size 5.7 KB

Snapshot excludes no files.
Snapshot excludes no directories.

Estimated upload time: 2m17s at 10 Mbit/s

Adding /mipsel in the .kopiaignore file works, but for certain reasons I don’t want to use .kopiaignore:

$ cat .kopiaignore
/mipsel

$ kopia snapshot estimate /home/user/static-binaries

Snapshot excludes no files.
Snapshot excludes 1 directories. Examples:
 - mipsel

Estimated upload time: 1m50s at 10 Mbit/s

I’m not sure if I misunderstood how the ignore rule works or it’s just a bug.