TR.EventStartDate had NaN value when gets RICs from "SCREEN" for get_data() request.
it works when specify RIC/RICs.
Interesting is works for price field even I use "SCREEN" command.
univers = 'SCREEN(U(IN(Equity(active,public))), IN(TR.ExchangeMarketIdCode, XTKS ))'
fields=['TR.CommonName','CF_ASK','TR.EventType','TR.EventTitle']
df,err=ek.get_data(univers,fields=fields)
df