Comparing training effect between Software Version

The table below shows 6 easy runs, two from each of version 22, 21 and 20. The runs are between 39 and 42 minutes long on flat ground.

SW Version Average HR Training effect (aerobic) Training load
22 137 0.6 11
22 136 0.2 4
21 142 3.5 128
21 139 3.0 85
20 137 2.8 68
20 138 3.0 82

For reference I am 71 years old, with a VO2max of 44, and a lab tested (October) lactate threshold of 165. I run 6 days a week / 5 hours currently on a 80/20 half marathon plan.

The feedback from Training Peaks is that I am executing the runs correctly, with 80% in pace and heart rate zone 2. But Garmin seems to overestimate my hard runs and not recognise the easy ones. As you can see from the above table. This started with v22 of the SW.