Any ideas why notification icons disappear?

I have the Kstatusnotifier/appindicator extension, so that it adds icons for things like Slack, Chromium, and Chromium’s Hangouts extension.

It works great on fresh boot.

But for some reason, after some time, the notifications/icons for Chromium and Hangouts disappear. The Slack icon seems to persist.

When it works, I see:

chromium-stuff-in-taskbar

and when it breaks I see less icons:

chrome-no-taskbar-icons

I think this happens when I suspend and come back, but I’m not entirely sure. I’ll need to pay closer attention.

Any ideas what to check?

Since this a third-party extenion, the Github repo is the right place to look. A quick glance shows a couple possibilities, maybe #170: Indicator stops working after screen lock