Pitfalls
There are some pitfalls, or known issues, you should be aware of when migrating from ScriptRunner for Jira Server/Data Center to Cloud.
For example, there may be instances where a JQL function on a server needs to be converted to a Cloud JQL keyword.
Asynchronous Event Processing
Asynchronous execution of functions and events means that any updates performed by scripts will happen after the page loads for the user. However, ScriptRunner has a feature that will notify users when issues have been updated. The order of event processing is not preserved, so when multiple scripts are triggered from the same event the ordering is arbitrary and will likely not be consistent.
Event Triggering
Updates made in scripts will cause events to be fired. This means that Script Listeners need to check values before updating them as the script may trigger due to a previous invocation of the same script.
Edit Screen
When using the edit issue API, fields must be visible on the Edit screen for the issue to be modified.