Yeah, just testing it again now, and it does trigger stuff like the Shield Deflection when blocking just fine.
Shield bash is another beast entirely I would imagine, as the default for a consumable type item like a wand or scroll in the main hand is trigger it. So Shield bash would be neglected in activation code wise I imagine as most would be wanting to wand or scroll for activation, rather than Shield bash if they have such an item in their main hand.
J1NG
:: edit ::
You could ask for a toggle option that would put Shield Bash ahead of activating the scroll or wand from the Devs, but I am unsure how easy that would be to implement (so it might be a very long time before you even get to see this option be made available).