That looks like Deadline can't find your Maya 2019 installation. It's not related to Prism. Probably your Deadline version is too old and doesn't support Maya 2019.
In the Deadline Monitor in the menu bar under "Tools" you can enable the super user mode. When that's enabled you can select "Configure Plugins" from the "Tools" menu. There you can select the "MayaBatch" plugin and check if there is a field for Maya 2019. If there is only a field for 2018 or 2018.5 and not 2019 you have to update your Deadline version.
There is a workaround to make it work with older Deadline versions, but updating Deadline would be the better way to solve that Problem.
That looks like Deadline can't find your Maya 2019 installation. It's not related to Prism. Probably your Deadline version is too old and doesn't support Maya 2019.
In the Deadline Monitor in the menu bar under "Tools" you can enable the super user mode. When that's enabled you can select "Configure Plugins" from the "Tools" menu. There you can select the "MayaBatch" plugin and check if there is a field for Maya 2019. If there is only a field for 2018 or 2018.5 and not 2019 you have to update your Deadline version.
There is a workaround to make it work with older Deadline versions, but updating Deadline would be the better way to solve that Problem.