Update 2018
Starting with Adaxes 2018.1, property display names are customized using the Administration console. For details, have a look at the following help article: https://www.adaxes.com/help/CustomizePropertyDisplayNames.
Original
Hello,
When we copied and pasted your text to a text editor, we noticed that there is something in-between and adm-CustomAttributeBoolean1. It is not a character, but something that seems like a random sequence of bytes that our text editor cannot recognize. In the editor, this looks as follows:
?adm-CustomAttributeBoolean1
This often happens when you copy text from somewhere, especially from a web browser.
There is no such an issue for adm-CustomAttributeText1, that's why the text attribute works, but the boolean doesn't. Just remove the whole line that reads adm-CustomAttributeBoolean1 and try typing it in manually. This should resolve the issue.