Yes, It is normal, We deliberately ignore this particular symbol.

Please see: https://easyeda.com/forum/topic/Net_and_Part_naming_conventions-uOHBvN5nh

@Tutorials OK, this makes sense, however, If you are storing the information in a JSON file you can use a simple programming trick to allow such characters. Simply replace any user entered "~" with a unique character like something not normally entered by a human like ascii character 7. Then when you display it back to the user reverse the conversion. I've used this technique as a software engineer storing information in XML files where the deserialization program barfed on certain characters, like single and double quotes.