The first thing I recommend doing if this issue is still happening is to follow the steps in the Twinmotion is not visible after splash screen article to reset Twinmotion back to a default configuration, in case a misconfiguration from a crash is causing the issue.
If the issue still occurs after that, please submit a bug report at https://twinmotionhelp.epicgames.com/s/case-community-page so our support team can investigate. be sure to include a copy of your Twinmotion.log file (Where to find Twinmotion .log file) as this can provide additional information about what may be happening.