Clearing field leads to a unicode conversion error message

[Thomas]

Hi there,

I am trying to remove certain fields by providing String::null to the setter
method as the documentation states:
"Sets the album to s. If s is String::null then this value will be cleared."

tag->setTitle(TagLib::String::null);

If I apply this function to a M4A file, the following message appears on the
console:
"TagLib: String::copyFromUTF8() - Unicode conversion error."

Is there anything I can do to avoid this output?

Kind reagrds,
Thomas