X_SIDE_EFFECTS_BY_USE_STALE
Means
a SIDE_EFFECTS_BY_USE row that no longer holds
Typical cause
the row names a module its package also lists in sideEffects (the array wins and the module rides in every chunk reaching the barrel), a module that runs nothing at import time, or one an entry imports bare (a bundler that honours the array drops a bare import of an unlisted module)
Fix
grep -n -A16 'SIDE_EFFECTS_BY_USE' scripts/side-effects.ts — delete the row, or delete the array entry, as the cause names