I have now had time to look into this in detail and I’ve found first that it’s hard as a user to work out what’s going on because the Playing Technique lane display in Play Mode only gives part of the picture. It shows which set of playing techniques from the expression map are being used, ie the entry in the Techniques table in the Expression Map Editor (internally we call these the ‘extrinsic’ techniques). However, we also have a set of playing techniques for which we have some fallback behaviour if they’re not specified in the expression map, such as accent and staccato (we call these the ‘intrinsic’ techniques).
What’s happening here is that for the second note, the current set of active playing techniques are a2 + staccato + accent. The playing technique resolving code has to find the best way of playing it from the set of available entries in the table, but there isn’t an exact match for it. Currently the logic that looks for a fallback only looks to see if you have an entry for a2 or staccato or accent. So it resolves this note to the a2 switch and then applies the staccato and accent intrinsics (ie play shorter and louder).
We don’t yet have any logic to deal with the case of matching a subset of all the techniques. This is what you are (naturally) expecting, so that it would resolve the note to use the a2+staccato switch and then use the accent intrinsic to play louder. Somewhat surprisingly, I think you’re the first person to discover this limitation in the whole 2.x application cycle. Now we’re aware of it I’ll log it and hope we can fix it in a future version. We’ll also try to find a way of showing more useful information in the Play Mode view so that you can get a clearer idea of what it’s actually doing. Unfortunately I can’t think of a workaround at the moment to get the effect you want, aside from dropping the a2+staccato entry, but I realise that’s not ideal either.