Hey @leonK-DI! Glad to hear it's working at least sometimes, but less glad to hear it's not working consistently.
I assume you've seen this post about our recommended updateMany workaround:
https://community.retool.com/t/mongodb-update-many-example/8889/2
When you say it's called several times, do you mean for the same record? Are there any specific error messages thrown in the debug console?
https://docs.retool.com/apps/management/concepts/debug-tools#console-tab