Start with the enclosure
Check the basics for Acanthoscurria geniculata: fresh water, suitable moisture, a secure retreat, good ventilation and a practical temperature range of 21–26°C. A clear husbandry problem matters more than a single evening of unusual activity.
For Giant White Knees, keep a water dish available and maintain a moderate moisture gradient; avoid both bone-dry slings and persistently waterlogged substrate. 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 Acanthoscurria geniculata, Giant White Knees 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 Acanthoscurria geniculata, 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 Giant White Knee repeatedly climbs or paces, check enclosure shape, moisture and recent disturbance. Mature males of Acanthoscurria geniculata may also roam much more after the ultimate moult.
One short burst of activity from Acanthoscurria geniculata matters less than a persistent pattern combined with poor body condition or an obvious enclosure problem.
Feeding changes
With Acanthoscurria geniculata, food refusal in Giant White Knees is often normal around premoult, after a heavy meal or following a rehouse. Keep water available and remove ignored live prey.
If Acanthoscurria geniculata 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 Acanthoscurria geniculata, visible injury, haemolymph loss, severe dehydration, inability to stand normally or major loss of coordination in a Giant White Knee deserves prompt attention.
If Acanthoscurria geniculata is physically deteriorating, correct any obvious husbandry problem immediately and seek experienced or veterinary help where appropriate.