I was playing with my friend (Master King Deaddude) in his non-dedicated, non-LAN server when he suddenly crashed (the message he got was WheeledVehicle::unpackUpdate()) ). The server remained on for several minutes until he tried getting onto his dedicated server (different server than the one I was on). This crashed his blockland and the server I was in (the non-dedicated server). But, before he crashed, I somehow managed to duplicate and plant 20 vehicles, which all successfully spawned. There were two other vehicles that other people had and were driving around in on the server. I was gunna take a picture of that, but my friend reset vehicles to fix the problem. I then attempted it again, and managed to get 40+ duplicated vehicles successfully spawned (plus the other two that people were driving around in). Right after I did this was when my friend tried joining his dedicated server. But, as I was in the middle of crash lag, I took a picture of what was in my field of view.
I got 36 vehicles captured in this shot. Unfortunately, Master started blockland again after crashing the second time, so no console log from him. But, I do have mine, in case that helps.
Also, possibly related to this issue: His server has had some odd issues with events. One door in particular that I made (which utilizes a simple VCE BL_ID restriction) does not open after being loaded from the save file. Also, I had made a clock tower with the typical simple events, and the events would not activate the correct Named Brick (I have four digits, 2 for hours, 2 for minutes. When the Ones minute digit was supposed to be activated, the Tens minute digit was). Stuff like that. His friend told him that some Custom Vehicle Support'd vehicles could be the issue for the message he got.