I have reported the Linux/Vulkan spline mesh rendering bug as case #00152785. Here’s a simple project that reproduces this bug, only under Nvidia driver 440.44 (the latest at the time of writing): https://iamestranged.com/distribute/support/SplineBug4-24.zip
It is not related to VR/lightmaps as one user reported above (that must be a separate issue).
I do hope this is an engine bug rather than a driver bug, it feels like the latter would take significantly longer to get fixed… 
Alan