I have always used WJST-X however after upgrading to EESDR3, I decided to try JTDX using TCI and I have noticed that in using TCI (instead of CAT with WSSJT-X), the VFO requency changes during TX and then goes back to the standard FT8 VFO frequency in RX however after some time (I don't know how long) the VFO frequnecy doesn't change back to the standard frequency. If you look at the attached image, you will see the radio stayed on 10.136.155 MHz, rather than go back to 10.136 MHz.

Does anyone know why this happens and how to stop it?

Under settings Radio split operation select rig
then it should be ok