Oracle Form Builder 12.2 shrinks .fmb when saved

Hello,

Hope you can help me. I'm using Oracle Form Builder 12.2 in Windows 10.

I'm trying to modify a .fmb file by only changing the behaviour of a trigger button modifying one line but when I save the file, the size of the file itself changes from 680 KB to 256 KB and that is causing us issues when trying to compile the FMB file with the following command:

frmcmp_batch module=$DIR/forms/ESA/FILE.fmb      userid=apps/******** output_file=$DIR/forms/ESA/FILE.fmx      Module_Type=FORM compile_all=Special

with the following error:

FRM-10043: Cannot open file.

The file is there and it exists but I think it is corrupted due to that change in size when saved.