If restart still works but the stable runtime keeps shrinking, the useful clue is the narrowing window itself, not the temporary recovery.
Restart success feels productive because it restores function. But in field service, the more valuable signal is often how little runtime the machine can now survive before falling back into the same weakness.
What this repeatable field pattern usually looks like
After reboot or cooldown, the system works again for a while. Then the same fault returns sooner than before under similar workload. Over time, the healthy interval becomes shorter, more predictable, and easier to trigger.
Why restart or cooldown can create a false sense of recovery
Because the machine recovers at all, teams treat the event as partial success. But a shrinking recovery window means the platform is becoming easier to destabilize under normal use, which is the opposite of reassurance.
What diagnostic order makes the pattern easier to isolate
Track the duration of stable operation across several cycles. Compare what changes that duration: heat, load, probe choice, user interaction density, or extended runtime. Trend matters more than one isolated recovery.
When the symptom is strong enough to justify parts suspicion
When the same operating conditions repeatedly shorten the stable window, the case for a runtime-sensitive hardware layer becomes strong enough to drive targeted investigation instead of generic reboot-based coping.