[2.3.0] Weird modifier behaviour, creating solid sections.
So I have a weird issue where a modifier will all of a sudden act crazy... and create it's own section in a print and treat it like a second part. It initially works, then as I'm moving up the model I'll change something unrelated and it will do this nonsense. All I'm doing here it creating a solid part of a model where a clamp is to go, I want solid infill where there's going to be clamping pressure. I know have to undo a bunch of steps and try and figure out what caused it, I'll post an image of what it's supposed to look like when I get it back to normal. Cheers.
This is what it's supposed to look like, I've just undone a bunch of stuff and will carry on stepping through until I figure out exactly when it goes cray cray. I'm more after why though 
Right... it's when I set the infill of another section that gets clamped (circular section to the right). They don't even interact with the same layer, but yet the cray is triggered.
Right, now it's doing some weird ass stuff where I delete the modifier settings and re-slice, but the slicer still acts like it's there.
I tried just adding perimeters instead of infill to see if it would still affect the other modifiers. Now I'm stuck with it, undo doesn't remove it, I'm going to start again I guess. Or reload it and see what happens.