Gabbard only entered into this entire "stop regime change" policy after flying to Syria to meet with Assad, without telling the American government she was going, only to return and refuse for years to condemn Assad as a murderer or as an enemy of the US. She never disclosed where the finances for this trip came from (not from the US government) and was granted a special audience with the dictator. Upon returning she began lying about the US involvement in Syria, claiming (falsely) that the US was directly funding Al-Qaeda and the Islamic State in its Syrian efforts to further undermine our stated goals in the region.
I don't know that she's "actually a foreign asset to an enemy state" but there are open questions as to: 1) why did she go to Syria to meet Assad, 2) who paid for it, 3) why did she lie when she said she sought clearance from House ethics prior to the trip, 4) why upon her return was she suddenly a de facto Assad mouthpiece - attacking the US for their involvement in Syria, and 5) why for years did she refuse to condemn Assad's brutal regime and refuse to call him a murderer?
These aren't normal actions from a sitting member of Congress and there is likely an underlying reason for why she took these actions.