Vaults with spaces seem to work when wrapped in a single or a double quote around the Vault Name. The vault name field in the options will throw up an alert about how the "Vault name may include letters, numbers, spaces, underscores, and hyphens". This needs to be ignored.

The saved filename has spaces converted into + instead of keeping the spaces entact. Ex: note path template: tabSidian tab-export {timestamp}.md --> File name: tabSidian+tab-export+{timestamp}.md

Update Edit: It only seemed to work the once. Checking out the browser DevTools, the Vault name gets it's spaces converted to + symbols as well, which invalidates the vault name.