I have updated to the latest 1.24 version, but the VNAV issue still persists. When I lowered the altitude to below 21,000 feet, the T/D indicator disappeared and the aircraft prematurely entered the DES mode.I conducted tests using the autosave file created in version 1.23. Subsequently, I will test with the file created under version 1.24. It can be said that this issue might still not have been resolved at present.