I tested with another user account and the shortcut worked as expected.
I tried deleting Spectacle’s shortcut settings and then re-adding them (via the + Add New v button. This results in the shortcuts not being available for the session. After restarting I still have the same issue though.
Are there any alternate ideas to resolve the settings issue without starting afresh? Thanks!
For the time being I am installing the qt5-qttools package using rpm-ostree simply to get this working. I did try resetting my shortcuts to defaults but all that did was ruin my workflow ; the Spectacle shortcuts still failed to work.
I worked it out; basically, I used KFind and searched for *spectacle* in my home directory. Anything that looked like a Spectacle config, cache, desktop file, etc. I removed. Then I removed the qt5-qttools package using rpm-ostree and restarted. Voila, everything works as expected.