I thought of this as well, I asked the previous owner where I bought the new terrarium from if the top screen is enough ventilation and he said yes, it’s just so little airflow so that may have caused her to wander alotIMO the spider is suffocating and trying to escape from a pool of Co2.
The spider alone doesnt generate enougn Co2 to suffocate, but every time you loom over and exhale into that tank you're flooding it with Co2
You need cross ventilation, not top ventilation. Co2 is denser than air so it sinks.