Hi Martin. Thanks. I will try to reproduce this bug next week.
Is it possible you haven't assigned a group track to each group? If you record one slot, jump right and the group track of that slot on the right is not set, it won't react (because it doesn't know where to record your stuff). Also make sure that you use CC mode "Toggle" when assigning the footswitch. I've discovered a bug that causes Playtime to jump right although it's not recording currently. I will fix that but it doesn't sound like the symptom you describe.
In Playtime 1.8.0, many bugs related to live-looping are fixed. Please let me know if you find any other ones.