Starting from Gerrit 3.3.0 messages sent via Reply dialog are posted as Patchset level comments (instead of Change messages), see [1-2]. It seems like a breaking change in Gerrit behaviour.

gerrit-trigger-plugin doesn't support such Patchset level comments, so posting comments via Gerrit web UI is triggering Jenkins jobs in Gerrit 3.2 and is not triggering in Gerrit 3.3.

[1] https://gerrit-review.googlesource.com/c/gerrit/+/266176
[2] https://gerrit-review.googlesource.com/c/homepage/+/288131