Project made in Stacks 4.1.x won't display in S4.0.x?

I’ve a project that was started when I was using S4.1.x. Due to crash issues I’ve downgraded to s4.0.x. All projects started in s4.0.x, opened and saved in 4.1.x, then re-opened back at 4.0.x are fine. But this one, which as I say was started in 4.1.x will open, but not page will display in preview. Neither in RW or a browser.

Is it feasible that a project started in 4.1.x will behave like this in 4.0.x?

Yes this was recently confirmed by Isaiah.

I downgraded from 4.13 to 4.04 after a crash and had that warning. I ignored it and so far so good, and I have now upgraded to 4.14.