I had the same feeling regarding a difference in FFB going from 11.2 to 50.4.
After updating, I immediately lost some pace on a car/track combo in iRacing I had been running all week (911+Watkins), and felt as if I wasn’t getting the same responsiveness from the wheel as before. Specifically, it felt like there was more latency, and I also felt like I wanted to turn the filter setting down. It almost reminded me of the latency that using irFFB in 360Hz mode introduces. I noticed that the car was wriggling more under braking, with me allowing the rears to lock more before I either reduced brake pressure or made a steering correction. I also noticed the car getting to higher angles of oversteer on corner exit before I was able to adjust there as well. This culminated in me driving a little slower, not getting as close to the edge.
Came to this thread specifically to see if anyone else noticed a difference in FFB with 50.4, so I’m glad I’m not the only one.
I reverted to 11.2, and placebo or not, it feels “normal” again after a few laps.
The only issue I now have is that my SimuCUBE doesn’t make the beeping sound it normally does after phasing.