Threaded Holes are faceted in STL result.
Solution
This is because they are helical b-splines (faceted segments). This is expected, the only way to remedy this is to go to Export Options for STL and adjust Tolerance Options to Custom or Fine. Will still be faceted but the results may be acceptable. However processing time will also increase.
Notes and References
Hardware/Software Configuration
Platform: INTEL
OS: windows
OS Version: XP32_SP2
Product: SOLID_EDGE
Application: TRANSLATORS
Ref: 001-9649001