sed temp file appears in nautilus but not in ls -a

**Expected behaviour**:
Temp files created by sed should disappear from Nautilus after automatic deletion

**Observed behaviour**:
Temp files showed in Nautilus for some time.

**Description**:

After using:
sed -i 's/CAD/cad/g' FILENAME

The temp files created by sed (sed#####) continued showing in Nautilus for some minutes (they disappear if I close and reopen Nautilus), and I could interact with them (see permissions, double click to open (which errored out by not finding an app to open it), but couldn't change them (move, change permissions, delete)

These temp files did not appear with ls -a.

The file is 3.6kb long.

The behaviour doesn't happen with: sed -i 's/cad/CAD/g' FILENAME but only with: sed -i 's/CAD/cad/g' FILENAME

**Outputs**:

>>>df .
Sist. Arq. Blocos de 1K Usado Disponível Uso% Montado em
/dev/sda2 459924552 235486388 201005512 54% /

>>>lsb_release -rd:
Description: Ubuntu 21.04
Release: 21.04

>>>apt-cache policy nautilus
nautilus:
  Instalado: 1:3.38.2-1ubuntu2
  Candidato: 1:3.38.2-1ubuntu2
  Tabela de versão:
 *** 1:3.38.2-1ubuntu2 500
        500 http://mirror.ufscar.br/ubuntu hirsute-updates/main amd64 Packages
        100 /var/lib/dpkg/status
     1:3.38.2-1ubuntu1 500
        500 http://mirror.ufscar.br/ubuntu hirsute/main amd64 Packages

ProblemType: Bug
DistroRelease: Ubuntu 21.04
Package: nautilus 1:3.38.2-1ubuntu2
ProcVersionSignature: Ubuntu 5.11.0-34.36-generic 5.11.22
Uname: Linux 5.11.0-34-generic x86_64
ApportVersion: 2.20.11-0ubuntu65.3
Architecture: amd64
CasperMD5CheckResult: unknown
CurrentDesktop: ubuntu:GNOME
Date: Thu Sep 23 15:51:04 2021
ExecutablePath: /usr/bin/nautilus
GsettingsChanges:
 b'org.gnome.nautilus.window-state' b'initial-size' b'(860, 495)'
 b'org.gnome.nautilus.preferences' b'executable-text-activation' b"'ask'"
 b'org.gnome.nautilus.list-view' b'default-column-order' b"['name', 'size', 'type', 'owner', 'group', 'permissions', 'where', 'date_modified', 'date_modified_with_time', 'date_accessed', 'recency', 'starred', 'detailed_type']"
InstallationDate: Installed on 2021-04-20 (155 days ago)
InstallationMedia: Ubuntu 20.10 "Groovy Gorilla" - Release amd64 (20201022)
ProcEnviron:
 SHELL=/bin/bash
 XDG_RUNTIME_DIR=<set>
 PATH=(custom, user)
 LANGUAGE=pt_BR:pt:en
 LANG=pt_BR.UTF-8
SourcePackage: nautilus
UpgradeStatus: Upgraded to hirsute on 2021-06-08 (107 days ago)
usr_lib_nautilus:
 evince 40.1-1
 file-roller 3.38.1-1
 nautilus-extension-gnome-terminal 3.38.1-1ubuntu1
 nautilus-share 0.7.3-2ubuntu3