FATAL: COLLAB_INTERNAL_KEY is not set

[victor-sm]

When starting the container the following error message is shown multiple times:

learnhouse-app | [collab] FATAL: COLLAB_INTERNAL_KEY is not set
learnhouse-app | App [learnhouse-collab:2] exited with code [1] via signal [SIGINT]
learnhouse-app | App [learnhouse-collab:2] starting in -fork mode-
learnhouse-app | App [learnhouse-collab:2] online

until:

learnhouse-app | Script /usr/bin/node had too many unstable restarts (16). Stopped. "errored"

The server process then attempts to start and seems to ignore the FATAL error. Adding COLLAB_INTERNAL_KEY to the .env file with a random secret resolves this error. It is unclear whether this is needed or not from the documentation. Can this FATAL error be ignored?