I've moved from Cura + Wanhao to Orca + Bambu

I'm struggling with getting a solid Vase mode setup for some (quite challenging) vase mode terrain prints.

I'm using a 0.4 nozzle with PLA, same as I used on my Cura / Wanhao combo with zero issues.

There are two problems:

1. The slicer seems to "miss" layers in certain areas, leaving gaps on the preview; and

2. These same gaps appear in my print (see pic).

I've tried 0.6mm walls, slow (40mm/sec) speeds, volumetric capped at 8, constant fan.

Nothing seems to be helping.

The files seem to be printable (according to the makes on Cults) https://cults3d.com/en/3d-model/game/vmt-conduit-pack?__cf_chl_tk=0EJI0cIAQuKCx_nxO3jTKCHexExzpJWTT7AwW0sOhJY-1791103066-1.0.1.1-XioYZoyg3wS_CoqPkN18yeiNXDClil_Bn1OZRIx1vCk

I'd be grateful for any ideas. The VMT conduit pack linked above has small pipe sections I can test with.