The cheque (check) specification takes on whichever Windows DPI (Display font) setting active the last time it was displayed. The following examples will cause the issue you discribe;

1. Created with Windows display setting to Normal fonts but then cheques are printed/previewed from a workstation using large fonts.
2. Created with Windows display setting to Large fonts but then cheques are printed/previewed from a workstation using large fonts.
3. Opening and saving a specification on any workstation using something other than normal font size.

Best course of action;
1. Get the specification fixed using a workstation set to Normal font size.
2. Make sure all workstations are set to use normal font size.