I'm running against a branch based off 18.1. The plugin version I'm using is the default for this branch, 1.2.4, which is also the same as what's checked in for the release18.1 branch, so while it's older than the latest trunk version it seems matched to the branch. I'll try updating to 1.2.5 (highest compatible w/ 18.1 according to your link) and see if this helps.

I actually updated to Intellij 2018 since this post and this made a dramatic difference as well. Thanks.