I can reproduce, thanks for the detailed STR. We're collecting history changes correctly, but sometimes don't write the flushed data to disk soon enough on shutdown. In theory the flushed data is sent to SessionStore at the same time with and without SHIP, but there may be some timing differences that are causing a delay. We may have to block shutdown on a final SessionSaver write. It's actually a little odd that this works perfectly with SHIP disabled. We'll still be saving the last ~15s of changes (or whatever browser.sessionstore.interval is set to), so I'm not sure if this has to be a hard blocker.
Bug 1724370 Comment 9 Edit History
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I can reproduce, thanks for the detailed STR. We're collecting history changes correctly, but sometimes don't write the flushed data to disk soon enough on shutdown. In theory the flushed data is sent to SessionStore at the same time with and without SHIP, but there may be some timing differences that are causing a delay. We may have to block shutdown on a final SessionSaver write (or figure something else out if that's not possible). It's actually a little odd that this works perfectly with SHIP disabled. We'll still be saving the last ~15s of changes (or whatever browser.sessionstore.interval is set to), so I'm not sure if this has to be a hard blocker.