Start with the enclosure
Check the basics for Phormictopus auratus: fresh water, suitable moisture, a secure retreat, good ventilation and a practical temperature range of 22–27°C. A clear husbandry problem matters more than a single evening of unusual activity.
For Cuban Bronze Tarantulas, maintain moderate moisture gradient with a water dish and strong ventilation. If the enclosure is obviously too wet, too dry or difficult for the spider to use normally, correct that issue before looking for a more complicated explanation.
Know what is normal
For Phormictopus auratus, Cuban Bronze Tarantulas are terrestrial tarantulas, so normal retreat use should make sense for that lifestyle. A hidden spider is not automatically a stressed spider, and a visible one is not automatically comfortable.
With Phormictopus auratus, changes from the individual's usual routine are more informative than a generic list of 'stress signs'. Compare activity, feeding and retreat use with what the same spider normally does.
Climbing, pacing and restlessness
If a Cuban Bronze Tarantula repeatedly climbs or paces, check enclosure shape, moisture and recent disturbance. Mature males of Phormictopus auratus may also roam much more after the ultimate moult.
One short burst of activity from Phormictopus auratus matters less than a persistent pattern combined with poor body condition or an obvious enclosure problem.
Feeding changes
With Phormictopus auratus, food refusal in Cuban Bronze Tarantulas is often normal around premoult, after a heavy meal or following a rehouse. Keep water available and remove ignored live prey.
If Phormictopus auratus stops eating but remains well hydrated and otherwise behaves normally, observation is usually more useful than repeatedly opening the enclosure and offering food.
Changes that need quicker attention
In Phormictopus auratus, visible injury, haemolymph loss, severe dehydration, inability to stand normally or major loss of coordination in a Cuban Bronze Tarantula deserves prompt attention.
If Phormictopus auratus is physically deteriorating, correct any obvious husbandry problem immediately and seek experienced or veterinary help where appropriate.