Looks to me like the issue is you are taking Field_1 and modifying it. Problem is, you cannot modify the size or type of an UPSTREAM ALREADY EXISTING field in a formula tool. Only in a tool with select functionality (select, Join, Multijoin, etc.).
What I do in these situations is to create a new field, maybe called "Field_1_modified", and there you can adjust your size and type.
See screen shot below. I went into the Input Data Options to File/Field Layout and clicked the ellipses. This opens the Flat File Layout dialog box. I then edited the Record Length there. I now the get the expected output.
While not precisely answering your question (I'm not using a formula tool), there are a couple of other options that you have.
If you have a file layout (metadata) that has your field list with type and size, you can use the CREW "Dynamic Metadata" macro. If you don't have a file layout, you can create one (and edit it) with the Field Info and Formula tools:
If you have a sample file that has the structure that you want to use, you can pull that file's structure and use a Union tool to 'force' the structure on your data file. The trick here is that your 'structure' file must be the first connection into the Union.