My general (unfounded) suspicion is that mob damage tables are mostly correct, but there is some sort of mitigation/damage reduction occurring that has yet to be explained. The only way the tiger could do regular damage to a higher armour Tips and 1-3 damage to joana is if there is some mitigation occurring for joana and not tips, or if they are on different shards/layers and for some reason the stats are different between the layers (extremely unlikely/impossible), or the tiger in the joana clip just happens to be born with a disability. But I should probably leave the baseless conjecture to the experts.
A demo of the game was available at BlizzCon 2018, and was downloadable on home computers for anyone who purchased a BlizzCon ticket or virtual ticket. The servers became available when Opening Ceremony started at BlizzCon 2018 and was set to end on November 8, but was extended until November 12. Players started at level 15, and the only available zones were Westfall and the Barrens. It was based on patch 1.13.0, essentially patch 1.12.0 ported to a modern infrastructure. The first day of the demo, there was a playtime limit of a cumulative 60 minutes with a cooldown of 90 minutes, applied through the BlizzCon Exhaustion debuff. The debuff was removed on the second day of BlizzCon 2018.