How to describe this unrecognizable content? [duplicate]

In programming, I got the following content which is unrecognizable in the output. When communicating with others, how should I describe the issue I encountered in more natural way?
In fact, this unrecognized contents should be other languages, like Japanese. For example, DeltaGundamk デルタガンダム。But the program didn't deal with this correctly.

Is garbled characters the term to describe these characters?

Chinese developers call it 乱码.
Japanese developers call it 文字化け(mojibake) .

Links:
1. Mojibake

Solution 1:

You might refer to unrecognised, unknown, unmapped, unexpected or unprintable characters. They may even, depending on the context, be obfuscated, or redacted by design.

Do you expect to see some other content in the highlighted areas? If so, what would you like to see there? The answer to these questions, could help you select among the above suggestions.

Solution 2:

I think they are commonly called unreadable characters. They are less commonly seen these days because unicode is commonly used in modern systems. Back then two decades ago, these unreadable characters are commonly seen in Chinese, Japanese and Korean languages systems because the character encoding for these languages extended ASCII mapping in their own ways and if the encoding is not selected correctly, such unreadable characters were shown. That is the reason unicode came to play, unicode standardized the character encoding for pretty much all characters in all languages. Most modern systems like Linux, Windows and macOS use unicde as their system character encoding, therefore, character encoding conflict is avoided so it's uncommon to see these unreadable characters these days.