Turn-Based Mode Bug: DR bypass not applied on attack used to initiate combat

My player character is a Cipher and I've generally been initiating combat (as in before turn-based mode begins) with an attack from stealth by her with Lead Spitter for the focus gain. However, I've noticed this opening shot consistently deals substantially less damage (even with Apprentice's Sneak Attack!) than subsequent attacks made with Lead Spitter on the same enemies. After reviewing the combat log, I saw that the damage calculation was not showing any DR subtracted from Lead Spitter's DR bypass on this initial attack (see image).

I also tested turning Turn-Based Mode off in the current beta patch, and this caused DR bypass to be correctly applied on this opening attack again, so this is specifically a TBM issue.