The category of Vulnerability Signatures that is most likely to trigger false positive alerts is:

C.info-leak

Information leakage signatures are designed to detect attempts to access or disclose sensitive information. These signatures can be prone to false positives because benign activities or legitimate data transmissions can sometimes be mistakenly identified as information leaks.

References:

Palo Alto Networks - Managing False Positives in Threat Prevention: https://docs.paloaltonetworks.com/pan-os/10-0/pan-os-admin/threat-prevention/manage-false-positives-in-threat-prevention

Palo Alto Networks - Vulnerability Protection: https://docs.paloaltonetworks.com/pan-os/10-0/pan-os-admin/threat-prevention/vulnerability-protection