On macOS, there were reports of Via crashing due to incompatible third-party software. The symptoms are often similar to the ones outlined in the following:
If this happens to you as well, you likely have Karabiner installed, which is not compatible with Java applications. Follow these steps to disable it:
Even if you do not have Karabiner installed but have the same symptoms, try to disable other applications listed in the Accessibility pane and see if it helps, as technically, the problem is not restricted to Karabiner only.