When importing a file to MTZ format using f2mtz or the import feature in the GUI, if using ctruncate to generate structure factors, the output MTZ doesn't include an F or SIGF column. This is a bug where the MTZ output from ctruncate isn't copied over to the output MTZ for the job. The fix is to replace the file $CCP4I_TOP/scripts/import.script with
*ccp4i-6.1.2-r5 (02 Nov 2009) 02 Nov 2009; Justin Lecher (jlec) <jlec@j-schmitz.net> +files/6.1.2-fix-f2mtz.patch, +ccp4i-6.1.2-r5.ebuild: f2mtz fix upstream #4061 b.g.o. 289379