If I may to add, cause this's Turkey's S-400 procurement saga is basically politics and no reasonable/undebateable military technical argument that can be put on arguing Turkish procurement of S-400 endanger F-35 secret.
Is basically CAATSA. Wish the American just say that, and don't argue on incompatibilty of the system or potential leaking of F-35 data. Saying potential leaking, seems saying Turkey is incapable to keep out Russian technicians on getting F-35 data.
This basically saying that Turkey is untrustworthy, while Greece is trustworthy even when they also operating Russian SAM system.
Greece acquired Russian system before CAATSA being enforced, while Turkey procured this after that.
Arguing on technical matters, just like they do it in Congress is degenerating to US Allies (if US still see Turkey is their Allies). Just tell Turkey this is a matter of CAATSA, thus US wants everyone that using their 'advance' Military equipment to follow CAATSA, and not buying any Russian equipment.
CAATSA is not having anything to do on technicality on integrating Russian Equipment with NATO's standard equipment. I believe Turkey is capable enough on their own to integrate Russian system with NATO standard equipment. As long as they can get the Russian to give them source code of S-400 then they can do it on their own.
In fact, seems Russia in this case that (in term on source coding secret) has more potential on Military technical Risk by has to share their S-400 source database with a NATO member. US in fact can benefit more with this, as they can (behind back door) to ask Turkey on S-400 technical as 'officially' Turkey is their Allies and not Russian.
Telling in congress on Turkish potential leaking of F-35 data to Russia by simply buying Russian SAM, is equivalent in Turkish public in saying that US don't trust Turkey on integrity issue.
From Turkey perspective, by saying on technical issue is the problem, they will say US bias on them, since they (US) have no problem on Greece using Russian system.
Just say this is CAATSA issue period, and don't put this argument on technical defense risk issue. If US really still want Turkey on their camp.