No, I use FG regularly and for that particular campaign once a month.
I will take your word for that it was split on April 2018, but according to a backup I have from Juli 13 of 2020, themes for Starfinder Pact Worlds were present in the non-player version of the module, as it was possible to create a character with the Roboticist theme with the main module as reference:
Code:
<themelink type="windowreference">
<class>theme</class>
<recordname>reference.theme.roboticist@Starfinder Pact Worlds</recordname>
</themelink>
<themerecord type="string">reference.theme.roboticist@Starfinder Pact Worlds</themerecord>
<token type="token">tokens/host/Player chars/Armogorashtakaz.png</token>
During a level-up
on April 10/11 2021, I find no indication of an error having accured when the theme was "re-applied" - the theme record was still as seen above.
During a level-up
today, an error occured when FG was not able to find said reference in the module. When trying to check the theme manually, it created an empty read-only record in the module.
The theme did not work until i manually updated the db.xml with
reference.theme.roboticist@Starfinder Pact Worlds (Players), so even if the split may have occured in April 2018, the main module must've had a full list of content and not just this:
Attachment 49086
Else, the character sheet could not have been created in the way it was, and the console would've displayed errors with each level-up.