As stated in the wiki, DM does DR an enemy hero for 0.325 sec. If DM gets interrupted, the UI (bottom left) stops counting even though the DR debuff still goes on.
As an example, Blaze’s Jet Propulsion does 58.49 dmg at lvl 3. It gets to 29.25 dmg when it’s DR from DM. At 0:18, the UI didn’t count that the Jet Propulsion was DR, but the debuff still took effect. She took around 28 dmg, if we look at her HP.
This has been around forever, I’ve reported it in I don’t know how many places.
The cause is that the interface for Defense Matrix only updates when Defense Matrix is applied to a target, and it applies every 0.0625 seconds, but the Defense Matrix debuff itself lasts 0.3125s, so it’s pretty common to see this discrepancy in action.
I was swearing it changed since the rework. I guess I never paid enough attention until 2 months ago.
Blizz plz fix BabyRage