OUTDATED AUTOSPY REPORT, IGNORE THIS: You're using models that are specifically made for 2.1 and expected them to work fine, which they don't, in fact.
Wait for the up and coming 2.2 update Jeck is cooking up. You're probably gonna have to wait for the first 2.2 patch, tho.
UPDATED AUTOSPY REPORT: "Models in 2.2's official release cause major gameplay impacting graphical issues, Which is a major factor in why my release is being held back." These are the words of Jeck Jims. Basically, models are broken in this release in general. They disappear, reappear and fuck things up.
AGAIN, looks like you gotta wait for 2.2.1.