It appears like there is a compatibility issue with plum-dispatch between GPJax and Cola. Cola wants to a cola-plum-dispatch v0.1.1 installed and GPJax install plum-dispatch v2.1.0. With both of these installs, Cola appears to unhappy and won't work. I have had to uninstall plum-dispatch v2.1.0 in order to get both GPJax and Cola to work together.
It appears like there is a compatibility issue with plum-dispatch between GPJax and Cola. Cola wants to a cola-plum-dispatch v0.1.1 installed and GPJax install plum-dispatch v2.1.0. With both of these installs, Cola appears to unhappy and won't work. I have had to uninstall plum-dispatch v2.1.0 in order to get both GPJax and Cola to work together.