Yup, this is what happens to me with my 6000xp and is my biggest complaint... I didnt know what was causing that.
So far this happens with the JK inverter BMS and the victron shunt mod that converts it into a fake BMS
I have been periodically changing the battery amp hours in the jk bms every once and a while.
When you change that setting it results in a guess of SOC. If you do that when its charging and the soc drift is going to cut off soon, it will charge to the BMS cell cut off voltage. and default to 100%.
After this, change your requested charge voltage to less than the previous 100% setting and then it will never read 100%
It is fvcked....
The only solution is to reprogram the JKBMS firmware to report 99% SOC during RCV Time when 'Controlled Float Mode" is enabled and switch it to 100% when entering RFV Time. Easily done and can be fixed by JK.......but.........well you know....no luck so far.