You were responding to me, and I most definitely didn’t equate the two. Maybe you meant to respond to someone else.
In any case, you can route between vlans (and subnets), but without a route you aren’t communicating between those vlans or.between subnets.
Also, you can have multiple subnets in a vlan, but you can’t have a single subnet across vlans.
The range (x.x.10.x and x.x.20.x from your example) is only the subnet side, you could have both of those subnets in one vlan. But you could not, for example, have x.x.10.x/24 exist in vlan 10 and vlan 20.
Was that the file transfer allowed for remote code execution one? That’d be the one that sticks out to me. 3 or 4 years ago iirc?
Edit: CVE-2021-27649 is the one that came to mind, not sure if that’s the one you’re referring to.