Distribution of the NAFF chaotic threshold for the TOI-4633 planetary system with different cases of i_mut between planet b and planet c. The histograms are drawn by integrating 5 × 10⁵ MCMC samples from N-body RV fitting for 1000 orbits of the inner planet b. NAFF threshold is the value above which the variations of the estimated mean motions are considered too large for the system to be stable on long timescales; when i_mut > 80°, the emerging narrow peaks are not Gaussian noise; instead, they could be discrete clusters of NAFF frequencies due to the extreme chaotic orbital parameter spaces. The fact that this is strongest for i_mut = 90° also suggests the dynamics are producing several preferred secular frequencies rather than one smooth distribution.