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I don't know what's happening but since the april update of the game I get mod warnings if not worse almost every session I play. It doesn't matter if I play the most recent version of the CE or an older one.
Seems the authors are so keen on putting out new content that they don't have time for basic testing and bug fixing.
Are you talking about Unity mods? Because they are not officially supported, at all, and it shouldn't be their responsibility to test unsupported third party mods.

Or are you complaining about the mod authors' lack of testing?

In any case, I have had to change the mods I use because of updates. Most mods are now part of the combined user mod, which I think supports the latest versions without warning or error.
If by "combined user mod" you mean the Community Expanion 2, I'm talking about that, and yes, I'm complaining about the mod authors.

For examle I never had any problems with readied cantrip attcks until I installed the CE version that patches problems with enemy saving throws. Now a readied cantrip (haven't tested ranged or melee) freezes the game.
And I don't recall any problems with the saving throws (game freezes when I cast fireball on several opponents) until I installed one of the previous versions.