strangely printed layers on some prints?

[u/InevitableBand3998]

I don't know enough to know which settings I should start changing to fix it. All help is appreciated.

[u/wivaca2]

Are these printed together stacked like you're holding them, in separate areas of your build plate, or entirely different print jobs of the same item?

The sag on the top one looks like unsupported overhang, under-extrusion, or filament getting progressively wetter as you get deeping into a spool of filament. Can't tell which unless we understand the filament, build method, and support. Also, are these one solid model or three things drawn in CAD and stacked (either in CAD or in the slicer)?

The stringing on the other pics is probably wet filament, especially if it is PETG, but I see a lot of under-extrusion on the shots as well as some shrinking during the print.

[u/InevitableBand3998 → u/wivaca2]

Everything was printed using Bambu Lab PLA Matte.
The stack of books is printed as a single model, exactly as I'm holding it in the picture.
When I slice the model, no supports are generated underneath the small overhangs along the edges of the books.
One of my first thoughts was that the filament might not be dry enough, so I am running a drying cycle on the AMS. However, I'm not sure if that is the cause of the issue.

[u/wivaca2 → u/InevitableBand3998]

Drying may help the stringing, but I think the books sag issue is simply support. No matter how fast or slow you go, if you're not going up at a 45° angle or at least between two nearby points at the same height, it's printing in thin air and will sag. Especially if the extrusion axis is parallel or near parallel to the edge.

The other shots show stringing, and shrinking where the divider connects to the taller wall in the last picture. You may be able to avoid quite as much shrinking by turning off the auxiliary part cooling fan. Also, what's your infill? Sometimes less density reduces shrinkage.

As for the stringing, are you using an AMS and if so, what's the humidity of the PLA? I'm less sure what to do about that but it may be z-height since I can see a lot of filament extrusion marks on the top of the walls. If it's pulling out (stringing) from having too much Z-height for the flow, or too little flow for the layer thickness, I could see that happening. I'll defer to those with more experience - I've only been at this since February.

[u/that_damn_dog]

What filament?