Ambient exploration music plays for several seconds, often very quietly, and then cuts out. Music sometimes restart with a different track and then will also cut out. This does not occur for set location music (Castle, Prydwen), combat music, or specific scene music.
As far as I can tell, this only occurs with day time exploration music, night time music tracks seem to play out fully and transition normally. I have found very few people who have experienced this bug recently except for a single Steam Discussion thread (https://steamcommunity.com/app/377160/discussions/0/691995483855555650/) which seems to link this issue to Load Accelerator. I do not use Load Accelerator. I do use High FPS Physics Fix but after uninstalling then reinstalling Fallout 4 and starting a new, completely new vanilla save (the 15 required DLCs for Unofficial Patch were active but the Unofficial Patch was not; no other mod, plugin, or even F4SE was active.) this audio issue persists. FO4Edit shows no mods in my load order touching music types or music tracks.
This was only noticed halfway through a save and then persisted through every subsequent new save starting on 1/10/26.