OpenGL - ACCESS_VIOLATION exception on glBegin() with new driver

We have a legacy application which worked for years with many NVidia GPUs and drivers.
Lately we installed the R460 U3 (461.40) driver for Quadro P4000 (on Windows Server 2016), and we are now getting an exception which we never saw.

We get the following exception:
0xC0000005: Access violation reading location 0x00000000.
On every call to glBegin().

We would appreciate any help with this issue.