Juha Bach is no fool, it's obvious he suspects "something" from Ishida whether he has yet to determine what Ishida is planning has yet to be said, but it's also obvious Ishida is suspect which is why he has set up precautions to make sure Ishida "Stays in line". Point is Ishida is most likely planning "something" but because all eyes are on him he is unable to act, and may very well assimilate into vanderiech without even knowing and then he might just become the final villain......... But that's a long shot, most likely he'll find a way to betray Juha Bach and Juha Bach will just pretend not to notice until Ishida attempts implement his "plan" and then Juha Bach will explain in some conveluted way how he knew Ishida would attempt to betray him and will try to either kill Ishida or make him reconsider, and then after that point it will be up to Ishida or rather Kubo.