So, I once again, took your profile, exported it directly, and ran with it (no change other than the window layout to match my monitor). My results are
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So much so that I know your first and second buttons on the shift bar is also set to sent SHIFT+1, rather than SHIFT+1 for the first and SHIFT+2 for the second. I'm not sure the problem here is ISBoxer. Do you have anything that could possibly be intercepting the clicks for that particular bar? I notice you are using a DPI scale of 200%. Is it possible that the clicks are not actually registering on where the bar is located? i.e. Have you configured ISBoxer Toolkit AND LOTRO to set the System option for the High DPI override (exit and restart after doing this)? How about trying a DPI scale of 100%? In either case you will need to create a new Window Layout to test it out after changing either setting - use the Window Layout Wizard.
To set the Override DPI scaling, you need to find each executable, right click on it, and select Properties, Compatibility, then tick the Override box, and select System from the list (not System Enhanced). Do this for both ISBoxer Toolkit.exe (you can do this on the ISBoxer Suite shortcut on the desktop) and lotroclient.exe (and/or lotroclient_awesomium.exe if you are using the Legacy option in the launcher) - for these, you need to find the exe in the Lotro install folder.
Note: for versions of Windows 10 more recent than my install, you have to click on a button on the Compatibility tab to get to another screen to set this option.