Essentially, when there is only one target and the Multi Strike hero is on the defending team, the damage is processing as a single strike only.
- Jabberwock vs. taunt
- Jabberwock vs. single opponent
- Bjorn vs. single opponent.
It only occurs when the multistrike hero is on defence (i.e. Jabberwock MUST be on defending team).
I’ll try to grab a screenshot but @Mr.Spock has also seen it occur (videoed?)
And this one shows Bjorn. Single damage shown only, not a double strike & two sets of damage.
Possible other heroes who MAY result in the single damage # shown: