Probably, someone else before me noticed that peculiar behaviour but I have not found any thread with a relevant title.
Anyway, here is the case. I have attached a screenshot which displays the number of shares that have been bought and sold for 07.02.2020 of Square Enix Holdings. Here is the link->>>interval 1d
As it can be observed volume value for the whole day is 1.53M.
However, if interval is changed to 1H instead of 1D the following volume values hours-wise are displayed:
2/7 9 AM: 515.8K
2/7 10 AM: 229.1K
2/7 11 AM: No volume at all
2/7 12 PM: 942.4K
2/7 1 PM: 236.6K
2/7 2 PM: 1.56M
If to sum it up, then the final value is 2.97 M.
It would be great if someone clarifies it to me.
Thanks in advance.