The data appears to be returned and then the browser runs a javascript to format the results. The formatting process takes so long that the browser may think the script is unresponsive and display an " long running script " error. The error indicates that the issue is not with the database, but with browser rendering.
The following three methods in the SBM Script Guide say that the return value for all of these is a Long Integer but in my testing it looks like these all return a Boolean value. The customer wants to know for sure because in their code they are trying to use the actual value without using an If statement. At the end is the appscript I used to test this and the value displayed in the event viewer was always "True" rather than a 0 or Non Zero.
The workaround is to not use the ts_internalname in the script (can't be modified after deploy), but to shorten the ts_name in Composer and use that in the script (this can be modified after a deploy).
Workarounds: Refrain from using the "Log On as Another User" when testing long redo messages Shorten the Shell.RedoMessage in the script or test with fewer unfilled required fields
So it looks like the underlying API does the correct thing by switching to a BLOB but the TS_CONTENT fieldf contains NULL instead of empty. The script used here is: Set objMessage = Ext.CreateAppRecord(Ext.TableId("TS_NOTIFICATIONMESSAGES"))