Colours in Power BI Service different for the exact same report in different tabs

This morning I noticed that the colours of some of my visuals in a published report are wrong and different from what I specified in Desktop. Yesterday they were still correct and I haven't made any changes.

The odd thing is that if I open the report a second time in another tab, the visuals with the issues are correct again but other visuals on another page are now wrong.

The new/wrong colours do respond to a colour in the theme colour pallette, but they aren't the exact colours we specified when building the report.

The problem visuals are just regular standard column charts and not all column charts are effected. I've tried republishing the report, but that doesn't help.

Please, if anyone has a solution or has any information, let me know.