That looks exactly like a solidity corruption. That is, like it or not there are a couple of points in your otherwise perfectly solid model that are SO close together that when you scale them down, the two points get ‘averaged’ to the same location in space- resulting in line segments with zero length and two points in the same space.
I have seen lots of errors like this over the years due to simple scaling down or up in an app that has a spatial resolution set too low.
That is- if two points are only 0.0015 mm apart- and your modeling space has a detail level of 0.001- then scaling that file down by 10% will result in those two points being averaged to the same coordinate.
No modeling space can juggle potentially infinite decimal places in its cartesian space- so every point in space is averaged to a certain number of decimal places.
On import- chances are that Preform ‘sees’ one or both of these as a hole and the point gets connected to some other point on the far side of the model that has an unconnected point.
The problem is- Preform does not generally RENDER these kinds of bridges caused by unattached points.
they show up in the print… but not onscreen-
If this is the cause, then you might want to try decimating your model before scaling it. I don’t know what resolution limit Preform is set to- but given that the printer can only deal with 25 micron layers- its likely not juggling a lot of decimal places when it coverts the model to printer profiles.
if its happening on import into preform or you are doing the scaling in Preform, once it has made this change to the model, scaling that changed model back up will result in the flaw scaling up, too. You will need to trash all the models that are printing like this at any scale.