Line 8734 was: select_new = (motion_sequence != null) ? select_new_in : false
This caused pass 2 (filter5(null, tsm, false, true, ...)) to enter the
!select_new path — finding best existing good tiles instead of untested
non-centered tiles — so nothing was ever selected and the centered-mode
loop was a no-op.

Fix: decouple select_new from motion_sequence null-check; only use_motion
is forced false when motion_sequence is null.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>