Where is listBullet added in Flow? https://github.com/wikimedia/mediawiki-extensions-Flow/search?q=listBullet&unscoped_q=listBullet
My guess is it's using a module defined elsewhere when is not setting targets on its ResourceLoaderModule.
After looking at this some more targets is indirectly the problem since VisualEditor loads different code on mobile and Flow is making assumptions about those being present.
The following dependencies need to be made explicit:
mw.loader.using(['ext.flow.visualEditor.icons', 'oojs-ui.styles.icons-editing-list' ]);