Here are the changes to the 2020 Clarity Plug-In Hybrid.

Great - thanks for checking,@ClarityBill

Perhaps there is an unseen algorithm that gets triggered in some circumstances. Like regen is sometimes pretty mild depending on the SoC and the temperature, etc. so perhaps the same battery protection software may intervene depending on the conditions, SoC, and mode selection. My experiment was on a mild May day with mid-range SoC% IIRC. I know for sure the needle stopped at the 7/8th dash in ECON but went 8/8 in SPORT.
Thanks for checking; there goes that theory...