Also there have been much publcised issues with futures trading on their platform, with a court ordering them to refund a large sum to an invester.
There also have been issues with outages:
"Unfortunately, the steep increase in client base and consequent surge in orders has led to several bottlenecks because Zerodha’s infrastructure has not kept pace.
The system conks off often and it is common to find traders expressing their angst against Zerodha, especially on days of high volatility.
Yesterday was a textbook example of this.
The news about hostilities between India and Pakistan led to a sudden surge in volatility.
Traders scrambled to take new positions or cover their existing ones.
However, Kite, Zerodha’s flagship trading system, was down and out.
It stopped taking orders, which is an unthinkable eventuality given the mayhem that was being witnessed in the markets at that time."
From https://rakesh-jhunjhunwala.in/zerodha-held-liable-to-compen...