Hello,
I’ve got a model admin setup in 2.4.0 (and 2.4.5) and an object (BeverageGroup) has a ManyManyComplexTableField to BeverageItem.
I’ve created a bunch of BeverageItems and go to create an BeverageGroup. I fill in the direct fields in BeverageGroup OK but when I check a few BeverageItems and click 'Add' the BeverageItems don’t stick.
I check them again and click 'Save' and they stick.
I’ve included a stripped down module which shows the issue.