"'Rider action': getting the action ready." when editing Razor views

When editing Razor files in Rider 2017.1.1 - or perhaps more specifically when editing embedded JS in a Razor file - I am often getting "'Rider action': getting the action ready. Press Esc to cancel...". This blocks from editing for about 10 seconds. It happens mostly when I paste something, though sometimes it's triggered just by hitting Enter or something else seemingly trivial.

This screenshot shows it happening. I've just hit Ctrl+V. The view is about 750 lines long, so not that big. The solution itself is pretty huge.