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.file_attr 1="1";

Building a project imported from CCES 1.1.0 to 2.3.0 I get this error:

[Error ea5004] "C:\Users\G\AppData\Local\Temp\acc3554de5a000\acc3554de5a001.s":659 Syntax Error in :
.file_attr 1="1";
syntax error is at or near text '1'.
Attempting error recovery by ignoring text until the ';'

It doesn't seem to be associated with the particular source file being compiled, it moves around. I can't view the temporary .s file as it is deleted immediately after the error. Any ideas what could be causing this?