I know there are a few columns in there which affect unit turning speeds (col 30-33 inclusive). If a tab character got accidentally deleted somehow (or one got inserted) and made all the columns after it slip out of register, so what was a combat stat value is now in the turnspeed column, then that would mess up their marching behaviour.

Obviously, if these columns have been left blank, then they're bound to not work, so simply clone the entries from a default unit type.

If you've logged all the various changes you've made in the past week, then maybe restore the last known UNIT_PROD where units behaved properly, comfirm it still works properly in battle mode (and, if not, then you know some other file is causing the problem) and then incrementally add the past weeks changes until the problem recurs.

Re: Column 53

I forget where I read this but there was a note of caution about editing entries in this column because of a non-standard ASCII character (it looks like a black rectangle, in Gnome) which can't be directly identified and thus is tricky to replicate, other than cut'n'paste from another unit's entry. It affects the parsing of columns and accidental deletion will affect all unit entries downstream of the error.

In other words, the majority of units still behave normally but some of the custom-made units which you tacked on to the end of the file (as per Gnome instructions) go wrong, indicating the error is somewhere in or near their entries.