Checked for overlapping lines - none found
I gouped the external lines as one group and grouped the mullions and transomes as another group and got the attached result.
Still no cigar
AC versions 3.41 to 25 (UKI Full 5005).
Using AC25 5005 UKI FULL
Mac OSX 10.15.7 (19G2021) Mac Pro-2013 32gbRam AMD FirePro D500 3072 MB graphics