Vbl chart change

Can anyone help me to understand, about the vbl chart. which was closed around 1170 9th june 2021 and on 10th it opens at 830 means stock was down 30% and was hugely volatile with a range of 781 to 918 but today on 11th june when I saw the chart of vbl of 9th june its closing around 785. How does that happened.

Impact of corporate action
Bonus share 1:2
ex-date 10 June 2021

Thanks for the response, but chart should reflect this yesterday itself. How does it is reflecting today. Is there any link or reference where I can understand the impact of various corporate actions.