It sounds unlikely to me that the exact same rendering error would happen only in C2's editor due to driver errors, on two separate computers with wildly different hardware specs that both have drivers up to date. But what do I know, I don't engineer computer hardware...
I double checked the CAPX I uploaded and it only happens now in the original project this started happening in. The CAPX I stripped everything out of isn't reproducing the error for me either,
I guess since this has already been moved to closed bugs before I could give additional input and I'm fairly sure it's not my computer to blame because of the above, I guess I'll just have to deal with it and complain every time I open the project and can't get it to stop when half my tree tops are missing in other layouts because of this bug. Thanks for your time.