Unable to obtain 'trsync_state' response

I have done some bugfinding using git bisect to see which commit introduces the bug.
I got this response:

983951443cf14fe2985585c2c2eb20efe526411d is the first bad commit
commit 983951443cf14fe2985585c2c2eb20efe526411d
Author: Kevin O'Connor <kevin@koconnor.net>
Date:   Mon Feb 15 16:02:40 2021 -0500

    mcu: Enable trdispatch infrastructure during homing

    Separate out trsync handling from endstop handling in mcu.py code.
    Enable the low-level trdispatch C code.

    This is in preparation for multi-mcu homing.

    Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

:040000 040000 09af92e0a03ad6a6046b59d73392f7ed3b1a3cd6 6168edc549087a953300ac04b5190ce4933ced39 M  klippy

The full bisect log:

# bad: [f2b4d353d859e0fc75a13b53050812516b06302c] rp2040: Add _ramfunc macro to internal.h and use in                                                                                                                                                         bootrom.c and chipid.c
# good: [c0d860487a70a05d44973d53a981e935ce7b3ad0] stepper: Remove set_tag_position() code
git bisect start 'f2b4d35' 'c0d86048'
# bad: [a0c27571dd0ff841a1464a7df05a8cdd7a2d135d] docs: Note previous firmware state issue with TMC22                                                                                                                                                        09/TMC2209 in TMC_Drivers.md
git bisect bad a0c27571dd0ff841a1464a7df05a8cdd7a2d135d
# good: [f00281d1e670e00ebcef06076abf2116c3f2d461] config: Fixes for generic-th3d-ezboard-lite-v1.2.c                                                                                                                                                        fg
git bisect good f00281d1e670e00ebcef06076abf2116c3f2d461
# good: [b6d8cf27d25faecfa47404924a757dc09e7a84a3] serialqueue: Add serialqueue_send_one() helper fun                                                                                                                                                        ction
git bisect good b6d8cf27d25faecfa47404924a757dc09e7a84a3
# bad: [d1665fae4f48519198fcd430d5fc18f17aee4e77] docs: Update Code_Overview.md with the removal of c                                                                                                                                                        alc_tag_position()
git bisect bad d1665fae4f48519198fcd430d5fc18f17aee4e77
# bad: [983951443cf14fe2985585c2c2eb20efe526411d] mcu: Enable trdispatch infrastructure during homing
git bisect bad 983951443cf14fe2985585c2c2eb20efe526411d
# good: [e1f7748e1a9dfda3e78f8a27e9972a9eb954e946] trdispatch: Support fast responses to trsync_state                                                                                                                                                         messages
git bisect good e1f7748e1a9dfda3e78f8a27e9972a9eb954e946
# first bad commit: [983951443cf14fe2985585c2c2eb20efe526411d] mcu: Enable trdispatch infrastructure                                                                                                                                                         during homing