You can try cracking them all loose and retorquing in a criss-cross pattern, like heads or intake manifolds. I've had this happen, and sometimes you just have to torque it in steps of ~5ftlbs or so, and kinda feel where the pulley is getting snug, and back off some. You can re-approach it after it warms up/heat cycles, and see if it settles in better. (Obviously, needs to be sealed enough to not leak coolant, unless that's blocked, but the clean surface usually seals for air/vacuum pretty well by 10+ftlbs.)
If someone has tackled this differently, chime in. I remember dealing with it a while back, but haven't had an M90 setup on my engines in a long time.
Torquing the supercharger down can be a tricky process. In addition to following the torque pattern and torquing to spec in increments, you must also keep spinning the blower by hand while torquing each bolt. If you feel resistance back off and go on to the next bolt. Unequal torque on the supercrager bolts can can cause rotor interference so accuracy is important.
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