@ab
Not really, unfortunately.

It seems to me that the current wifi kernel module is unable to correctly interpret one or more of these ASCII characters and since it's a closed source component, you cannot examine it to find out why.

You might want to log a ticket on the Onion helpdesk and provide them with these ASCII characters, together with a pointer to this thread and a request to troubleshoot the wifi module. Perhaps that way they can enhance the module with some new functionality or a bug fix, whatever may be necessary?

Apart from that, or perhaps changing your SSID's, I'm not really sure what else to suggest.