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If you place this structure and open the doors then graphic errors appear when closing. This seems to have something to do with VBO.

After some testing this only happen with the door activator.
After even more testing it do not happen if I make both door close and open by using signal.

Need to precise here that there is a slight disappearance of the door when n opening/closing the doors at the same time with signal but not near as bad as door activator

It must be a problem with the door activator

If you give the doors "Stay Animated" and then connect them to the Door Activator there is no problem anymore. I didn't test this with this example but I had a similar one with another door.

Fixed in the newest pre-release.