Created a multiblock machine that is successfully recognized (MM creates a blueprint for it ingame and Controller says Structure Found), however whenever I try to right click the blueprint to view the preview, my game crashes. I suspect that it has to do with using the slopes / slants from BlockCraftery.

Here's the log: https://pastebin.com/UJ7L20C0

Have the same problem with Immersive Engineering Iron Sheetmetal:

https://pastebin.com/q6Refnku

MC 1.12.1
Forge 2484
MM 1.5

Just a note, it also had Iron Sheetmetal Slabs which are even more likely to have caused the issue.