Back test error during market hours

Dear Friends,
I’m using Zerodha Pi last one month. It’s actually generating false buy/sell calls. Actually I’m finding this issues after market hours only.
I’ll check the back test with same EA after market hours and buy/sell signals missing where actually got generated during market hours.
So I decided to check back test once before taking a call. But issue is actually back test not working during market hours.
Just want to know why…?