When coupled with Lost Cities, Wroughtnaut's Chamber, Barakoa Village, and Frostmaw do not spawn.

This was tested on Forge 36.1.32 with the latest version of both mods.

I should clarify also - I am not trying to spawn Mowzie's structures in the lost cities. Installing lost cities makes mowzies stop spawning in the Overworld or at all as far as I can tell.

I am also having this issue, in particular after installing lost cities and creating a new world, where before everything worked perfectly. Any updates?

I'd like to comment how i managed to make the frostmaw & the sun chief spawn in a lost cities world.
However my modpack contains a ton of structure adding mods. It's sort of like rlcraft. I did not jet find a Wroughnaut but i don't expect everything to spawn/generate smoovly with all the structure adding mods i'm tinkering with.

Anyway, i think the most important thing to notice is that i used the "rarecities" profile (including biomes o plenty & traverse) as the regular overworld. I made sure to deactivate the lost cities dimension in it's configs. I don't think any other profile would work for mowzies mobs, as the cities take far to much space for additional structures.

Anyway i'm glad mowzies mobs comes with an easy to understand config file. It helps a lot.

Edit: after i changed the Wraughtnauts generation condition to the max possibility, i also found that mob/structure. I was testing this using the current version of mowzies mobs for 1.12.2 & the following lost cities mod: 2.0.22 for 1.12.2

As i said earlyer it is unlikely for structure adding mods to add their content to a lost cities world other then one of the "rare cities" profile. Unless you have something weird in mind, like an ocean only thingy. But then again you wouldn't be reading this.

Mowzies mobs & lost cities work just fine. Lost cities just takes insane amount of space for structure generation, keep that in mind!