Heart Rate Zones overlap

Since a couple of weeks my heart rate zones overlap and I can not get it fixed. Also it does not matter if I choose BPM or %HR, it always overlaps. So for example one Zone ends at 90% the next one starts at 90% and not at 91%. Same for BPM values, see the image. I can reset the zones all I want, trying to set them by my own but since you can only change one value, the next zone always starts with the same value the last zone ended. So if I run at 137bpm I run in aerobic zone AND in the Threshold zone which I see then afterwards in my stats in Garmin Connect. This is crazy and I just noticed it a couple of weeks ago. Before I didn't had this problem. How can I fix that? I din't had this problem before...

Using an FR 965 with Software 20.32 and the HRM Pro Plus.