Looker charts displaying null value, not seeing missing data section under style panel

[PabloBMG]

Hi everyone so my charts in Looker Studio are displaying incorrectly, can you help?

The problem is that my charts start with a "null" value that seems to report all data prior to the date range selected. How can I fix it? Here are a couple of examples.

Example 1

Example 2

I've checked several tutorials online, and all of them mention using the "missing data" section, but I do not see that section when I try to edit my charts. What might be the problem?

[PabloBMG]

bump.

[PabloBMG]

bump.