Only if not already created: a new tyCache object

[tyFlow]

The check function takes the fully-resolved input path of all tyCache objects in the scene and does a lower-case comparison to the fully-resolved output path - if a match is found, a new tyCache object is not created. If repeated exports are continually re-creating new tyCache objects with that option enabled, then some part of your output path is changing when it's being resolved...hard to guess what, though. You can test with a more benign output path (ex: "C:\temp\output.tyc") to compare whether the function is working in principle.