Switching to new input method does nothing

I have ibus-m17n installed, but switching to a different input method does nothing.

STR:
1. Make sure my 2nd input method (in my case, "Sanskrit (sa-IAST (m17n))" appears under "Settings-->Keyboard-->Input sources."
2. Use alt-space to switch to my second input method.
3. Notice on the top panel that the indicator shows that the input method has changed.
4. Attempt to key in some special characters (using Gedit, LibreOffice, etc.).

Expected result:
The special characters will appear.

Actual result:
The keyboard behaves as if the input method were my usual "English (US)."

No such problem with 22.04.

Removing and re-adding "Sanskrit (sa-IAST (m17n))" in Settings doesn't solve the issue.

Hardware: IBM ThinkPad Carbon X-1, 5th generation.

ProblemType: Bug
DistroRelease: Ubuntu 22.10
Package: ibus 1.5.27-2
ProcVersionSignature: Ubuntu 5.19.0-21.21-generic 5.19.7
Uname: Linux 5.19.0-21-generic x86_64
ApportVersion: 2.23.1-0ubuntu3
Architecture: amd64
CasperMD5CheckResult: unknown
CurrentDesktop: ubuntu:GNOME
Date: Sun Oct 23 08:44:46 2022
InstallationDate: Installed on 2017-12-08 (1779 days ago)
InstallationMedia: Ubuntu 17.10 "Artful Aardvark" - Release amd64 (20171018)
ProcEnviron:
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: ibus
UpgradeStatus: Upgraded to kinetic on 2022-10-21 (1 days ago)