Timelion cusum not working with log?

I have created a graph in timelion that generates daily returns using data from an index that keeps the daily balance of an account. The code is the following:

.es(index=daily_account,q="account:1794",metric=sum:daily_pnl,timefield=date_closed).derivative().precision(8).divide(.es(index=daily_account,q="account:1794",metric=sum:equity,timefield=date_closed).precision(8).subtract(.es(index=daily_account,q="account:1794",metric=sum:daily_pnl,timefield=date_closed).derivative())).plus(.static(1)).precision(8).log(2.71828)

The code works fine and returns a line with returns on a daily basis. When I try to get a cumulative sum though of the above by adding .cusum(), nothing is returned. I was wondering if there is an issue with using log and cusum together but I could not find anything. Any ideas will be greatly appreciated.
Kibana version: 6.8.10

There isn't any know issue that I'm aware of. Can you check the request made by Timelion in your browser's network tab and post it here? We can try and debug from there.

Thanks for your response @Marius_Dragomir, your request actually showed me the way to find the cause. The initial request has null value in the first bucket, which is the reason the cusum request fails. Not sure if this the expected behaviour, nevertheless I applied a condition to replace with 0 if null and now cusum() works.

Thanks a lot! You can consider this issue closed.

That sounds indeed like not an expected behavior. Can you open an issue here please? https://github.com/elastic/kibana/

Issue created https://github.com/elastic/kibana/issues/87077