In the new timeline design, if I create a new era, I keep getting the warning sign 'Current Era cannot wrap around any other era' even if the previous era was 5 years ago.   I increase it's start by a year to see if that helps, which it does initially, and then if I try to change the colour of the era, or write any text, the same warning comes up again, and I have to increase my era by another year to allow my timeline to save. It won't save if there is an error with the era it seems.

Make a new era

Get a warning sign when you try to have it follow immediately after the previous era

Move era start forward by a year (now get a year of greyness between 2 eras)

Try to change the colour of the era

Get the same warning sign that eras can't overlap

Move the era forward by another year, it accepts so you change the colour again

Get the same warning sign that eras can't overlap even though you're several years away from the previous era now.

Make a text change to the era... and then get the same overlapping era message