Some of my apps aren't showing up in the Start8 most-recently-used list. Google Chrome is one example. It isn't pinned anywhere, it just never shows up, no matter how many times I run it. (Obviously I can launch it via All Programs.) This is a newly built laptop running windows 8.1 now, previously I was running Windows 8 with Start8 and Chrome showed up like any other app would.

I just noticed Excel doesn't show up, either, although Word does. I can't say I see any pattern. I messed around with pinning and unpinning shortcuts but that doesn't seem to have any bearing on the issue. They pin or unpin fine, and other apps which do show up don't change after pinning/unpinning.