Webhook-only app event user.signed_out is not triggered under browser

Using a custom unpublished webhook-only app, the event user.signed_out is not triggered (nothing in the webhooks log at all) under browser (client_type: browser). Then event user.signed_in is working fine. And user.signed_out is also working when using the Windows or Android application (client_type: win or android). Can this be a (known) bug or a browser specific behavior? Thanks!

I just found that it works when we log out from https://zoom.us/ as intended, but not from https://marketplace.zoom.us/ (where I was to manage the app)…