Historical Rules · 23 August 2019
Rule 702.15e
Official source text from the 23 August 2019 Rules release
If multiple sources with lifelink deal damage at the same time, they cause separate life gain events (see rules 119.9–10). Example: A player controls Ajani’s Pridemate, which reads “Whenever you gain life, put a +1/+1 counter on Ajani’s Pridemate,” and two creatures with lifelink. The creatures with lifelink deal combat damage simultaneously. Ajani’s Pridemate’s ability triggers twice.