Chart Multi-level category problem

Hi all,
I have a problem with a chart with multi-level categories.

It is a chart where I compare the status between January and April for 4 years (2016-2019).

For some reason the last category is segregated as you can see in the screenshot.

In the table, all columns are identical …

Thanks for your support.

I'm unable to replicate this. Any chance we could see a desensitized version of the workbook?
Easier to diagnose that way.

BSB

Here's the xlsx file.