When a customer i merged i NetSuite, I can see it in the UI "System Information" > "System notes", but not when I query the

SystemNote

table with SuiteQL. Anyone know where I can find this ?

Just a thought since I've had some fun with system notes in suiteql. Are you running the query in the administrator role? Systemnotes via suiteql is a little tricky because it requires admin privileges to return the values

Yes. I am running as administrator