Is that DeepL’s app? I’ve never used it so I have no idea what the UI looks like and I didn’t try to translate the sign’s text with the web version.
Edit: out of curiosity I tried out how the web version handles this sign:
Yeah, it’s the android version.
To be fair, It looks like a problem with the OCR from the app rather than the translation. When I use the phone’s native OCR and copy/paste the text into DeepL Translate, I get the same result as you.