Underscores in comments are removed

### Problem

When importing, any underscores in the comments field are removed.

### Setup

* OS: NixOS 25.05.20241125.4633a7c (Warbler) x86_64
* Python version: 3.12.7
* beets version: 1.6.1
* Turning off plugins made problem go away (yes/no): No

My configuration (output of `beet config`) is:

```
copyartifacts:
extensions:
- .jpg
- .lrc
- .txt
- '*/*'
print_ignored: yes
directory: ~/Music_new

import:
copy: yes
paths:
default: $albumartist/$albumartist - $album ($year.$month.$day)/$disc $track $title

# --------------- Plugins ---------------

plugins:
- copyartifacts
- lastgenre
- scrub
- zero
zero:
keep_fields:
- title
- artist
- arranger
- composer
- lyricist
- album
- albumartist
- disc
- disctotal
- track
- tracktotal
- year
- month
- day
- genre
- genres
- asin
- catalognum
- catalognums
- country
- isrc
- label
- language
- languages
- media
- script
- comments
- art
- images
update_database: yes
auto: yes
fields: []
scrub:
auto: yes
lastgenre:
whitelist: yes
min_weight: 10
count: 1
fallback:
canonical: no
source: album
force: yes
auto: yes
separator: ', '
prefer_specific: no
title_case: yes
```