Reading the early DMG released today, I noticed the rule about Combining Game Effects was not included. I'm referring to this rule from the 2014 DMG:

Combining Game Effects

Different game features can affect a target at the same time. But when two or more game features have the same name, only the effects of one of them—the most potent one—apply while the durations of the effects overlap. For example, if a target is ignited by a fire elemental’s Fire Form trait, the ongoing fire damage doesn’t increase if the burning target is subjected to that trait again. Game features include spells, class features, feats, racial traits, monster abilities, and magic items. See the related rule in the “Combining Magical Effects” section of chapter 10 in the Player’s Handbook.

I know that in the 2024 PHB we have a rule about Combining Spell Effects (similar to the one from 2014), but it's related to spells, not other game elements.

I think it's worth mentioning that the section was included as an erratum in the 2014 DMG. So, if it was added before because WotC considered it was relevant, why is it not necessary now?

That's unfortunate as Combining Game Effects was far more inclusive by encompassing various game features that the related rule in PHB.

Quote from Plaguescarred >>

That's unfortunate as Combining Game Effects was far more inclusive by encompassing various game features that the related rule in PHB.

 I think so too :(