Multiple omitted variable in EVENTDD

[Dayla Spassio]

hello i am conducting a panel event study with the eventdd command following the work https://docs.iza.org/dp13524.pdf ( Damian Clarke @Kathya Tapia Schythe ). However, only one variable should be omitted, as suggested by the paper (affirms "[...] A single lag or lead variable is omitted to capture the baseline difference between areas where the event does and does not occur. [...]"), but STATA omits two variables, the baseline one and another. Why?Solutions? Suggestions? Thanks