Well, I can't tell you exactly - this happened to me in UT2004 editor. I created subclass for weapon pickup base and when I checked superclass (that is class that your class is derived from - you should know what you derived it from) and looked at the code. There I'd found it takes value from properties, so I changed them for my class... ok, mmnt. I'll start UT2004 editor.
See the attached picture:
1 - When I realized that "something" is scaling my weapon base static mesh down, I tracked it down and found this code in xPickUpBase. It takes value from default properties. 2 - As you can see, in xWeaponBase DrawScale=0.5. That was the problem. Originally I thought I'd have to change the code. But it was much easier.
3 - I had my subclass already created - I believe you have your own class too. It inherited values from superclass (in my case xWeaponBase). I'd already changed static mesh.
4 - But I forgot to change this.
When I created my level, I simply scaled all pickup bases to 1. But when the level started 0.5 from default properties applied.
I don't know if something similar happens to you. I'm sorry to mislead you if not. But it just sounds similar to me. I don't know what changed from UT to UT2004 though. I can't help more than this.