Compressor (4.6.3) on Ventura (13.3.1) doesn't respect bit-rate on MP4

I haven't tried this with anything but H.264 encoded MP4s, but recently I've been having this problem where I tell compressor I want a specific max bit-rate (e.g. 6500 Kbps) and I get a much higher rate (e.g. 19 Mbps). It doesn't matter what I set the max bit-rate to, I get the same size file.

I *can* compress the same input on another version of compressor (another computer) and it works as expected. It doesn't happen all the time, but it does fail after restarting the computer, and it fails over and over. I'm not sure if the source file (duration?) has anything to do with it, but I know it worked correctly on at least one video I compressed recently, so I know it doesn't happen all the time.

The most recent example was a 21 second 1080p video that I exported from Davinci as ProRes 422HQ because, and this is interesting, Davinci Resolve Studio has exactly the same problem and produces the same result when I try to export as an H.264 MP4.

I am sure this problem just appeared since a recent OS update (from 13.1 to 13.3 Ventura?). Before the "upgrade", I've never had this problem with Compressor or Davinci.

I'll attach a screen capture with the compressor settings and the bit-rate of the resulting video according to QT