Where does the "memory leak" + 1GB per hour come from?

Question

Node.js

There is an application on NuxtJS. As per the timer, +1GB is added every hour. Launched via PM2. Googled similar issues, but complained about GC not starting in PM2 - unconfirmed information. Launched through Forever, the problem did not go anywhere. Exactly every hour + 1GB. And jumps. Within an hour, the application works within 300 MB and immediately becomes 1300, then 2300, then 3300 + -, etc. depending on how much memory is allocated before restarting.
Maybe someone heard something or faced a similar problem.
P.s. It feels like every hour the application starts some task, which then "is not cleared", but such operations are not provided by the application logic.

Debian 10
node v14.17.4
The project uses MongoDB. The occupied memory space is about 5.5GB