Incremental refresh corrupting data

[yesoriginal]

I have a large table with data (more than 20 GB). So I set up incremental refresh. Everything works fine, but for the last 3 months the data for the first day of the month for some reason doubles.
Maybe someone has encountered this?
In the desktop version, if you remove the filter from Power Query by date - everything is displayed fine.

[Deku · Accepted solution]

Incremental refresh requires

• >= RangeStart
• < RangeEnd

Please check if this is misconfigured.

If not have a look at the source system

[Deku · Accepted solution]

Incremental refresh requires

• >= RangeStart
• < RangeEnd

Please check if this is misconfigured.

If not have a look at the source system

[yesoriginal · Accepted solution]

Yes, that helped. Thank you very much.
I had
>= RangeStart
<= RangeEnd

[Deku]

Been there, done that