I just checked this in Reaper, using both standalone alone, standalone with Reaper running, and plugin in Reaper. Win 7 here. Focusrite Scarlett 2i4 audio interface.
Not experiencing this at all.
Perhaps it's related to audio settings then? Change buffer size maybe?
Relatedly, my Reaper default project has a brickwall safety on the master, AND i put a brickwall on all my instrument presets, just to be safe. (I did remove the brickwall's to check this issue)