Thanks GoingAway. Only thing I can think of is my citizenship - I am PK but PRC holder and have been in US for 5 yrs now (all with same company that brought me here in the first place). No unusal travel patterns either unless they think going back to visit my parents in PK once in 2 years is 'unusual'...

Thinking of first approaching CBP with FOIA request to see what 'declined' me.

If anyone else has suggestions, ideas or experiences, feel free to PM me. Thanks!